Endothelial dysfunction is related to aldosterone excess and raised blood pressure

Salt and Aldosterone - Reciprocal and Combined Effects in Preclinical Models and Humans

Primary aldosteronism is an endocrine disorder caused by excessive production of aldosterone by the adrenal glands, and is recognized as the most important cause of endocrine hypertension. With specific therapy, this type of hypertension is potentially curable. In the general population, high salt intake increases the risk for cardiovascular diseases like stroke. In populations with aldosterone excess, observational and experimental data suggest that aldosterone-induced organ damage requires a combination of high dietary salt intake and high plasma aldosterone, i.e., plasma aldosterone levels inappropriately high for salt status. Therefore, understanding the relationship between plasma aldosterone levels and dietary salt intake and the nature of their combined effects is crucial for developing effective prevention and treatment strategies. In this review, we present an update on findings about primary aldosteronism and salt intake and the underlying mechanisms governing their interaction.

Cardiovascular complications in insulin resistance and endocrine diseases

Cerebrovascular diseases, such as stroke and cardiovascular disease, are one of the leading causes of death in Japan. Type 2 diabetes is the most common form of diabetes and an important risk factor for these diseases. Among various pathological conditions associated with type 2 diabetes, insulin resistance has already been reported to be an important risk factor for diabetic complications. The major sites of insulin action in glucose metabolism in the body include the liver, skeletal muscle, and adipose tissue. However, insulin signaling molecules are also constitutively expressed in vascular endothelial cells, vascular smooth muscle, and monocytes/macrophages. Forkhead box class O family member proteins (FoxOs) of transcription factors play important roles in regulating glucose and lipid metabolism, oxidative stress response and redox signaling, and cell cycle progression and apoptosis. FoxOs in vascular endothelial cells strongly promote arteriosclerosis by suppressing nitric oxide production, enhancing inflammatory response, and promoting cellular senescence. In addition, primary aldosteronism and Cushing's syndrome are known to have adverse effects on the cardiovascular system, apart from hypertension, diabetes, and dyslipidemia. In the treatment of endocrine disorders, hormonal normalization by surgical treatment and receptor antagonists play an important role in preventing cardiovascular complications.

Mineralocorticoid receptor antagonist treatment improved arterial stiffness in patients with primary aldosteronism: a cohort study compared with adrenalectomy

Background

Elevated arterial stiffness in patients with primary aldosteronism (PA) can be reversed after adrenalectomy; however, the effect of medical treatment with mineralocorticoid receptor antagonist (MRAs) is unknown.

Objectives

The aim of this study was to evaluate the effect of MRAs and compare both treatment strategies on arterial stiffness in PA patients.

Design

Prospective cohort study.

Methods

We prospectively enrolled PA patients from 2006 to 2019 who received either adrenalectomy or MRA treatment (spironolactone). We compared their baseline and 1-year post-treatment biochemistry characteristics and arterial pulse wave velocity (PWV) to verify the effects of treatment and related determinant factors.

Results

A total 459 PA patients were enrolled. After 1:1 propensity score matching for age, sex and blood pressure (BP), each group had 176 patients. The major determinant factors of baseline PWV were age and baseline BP. The adrenalectomy group had greater improvements in BP, serum potassium level, plasma aldosterone concentration, and aldosterone-to-renin ratio. The MRA group had a significant improvement in PWV after 1 year of treatment (1706.2 ± 340.05 to 1613.6 ± 349.51 cm/s, p < 0.001). There were no significant differences in post-treatment PWV (p = 0.173) and improvement in PWV (p = 0.579) between the adrenalectomy and MRA groups. The determinant factors for an improvement in PWV after treatment were hypertension duration, baseline PWV, and the decrease in BP.

Conclusion

The PA patients who received medical treatment with MRAs had a significant improvement in arterial stiffness. There was no significant difference in the improvement in arterial stiffness between the two treatment strategies.

Cardiovascular outcomes and all-cause mortality in primary aldosteronism after adrenalectomy or mineralocorticoid receptor antagonist treatment: a meta-analysis

BACKGROUND

In patients with primary aldosteronism (PA), long-term cardiovascular and mortality outcomes after adrenalectomy vs mineralocorticoid receptor antagonist (MRA) have not been compared yet. We aim to compare the clinical outcomes of these patients after treatment.

DESIGN AND METHODS

A systematic review and meta-analysis was conducted by searching PubMed, Cochrane library, and Embase from no start date restriction to 18 December 2021. Our composite primary outcomes were long-term all-cause mortality and/or major adverse cardiovascular events (MACE), including coronary artery disease (CAD), stroke, arrhythmia, and congestive heart failure. We adopted the random-effects model and performed subgroup analyses, meta-regression, and trial sequential analysis (TSA).

RESULTS

A total of 9 studies with 8473 adult patients with PA (≥18 years) were enrolled. A lower incidence of composite primary outcomes was observed in the adrenalectomy group (odds ratio (OR): 0.46 (95% CI: 0.38-0.56), P < 0.001). We found a lower incidence of all-cause mortality (OR: 0.33 (95% CI: 0.15-0.73), P = 0.006) and MACE (OR: 0.55, (95% CI: 0.40-0.74), P = 0.0001) in the adrenalectomy group. The incidence of CAD (OR: 0.33 (95% CI: 0.15-0.75), P = 0.008), arrhythmias (OR: 0.46 (95% CI: 0.27-0.81), P = 0.007), and congestive heart failure (OR: 0.52 (95% CI: 0.33-0.81), P = 0.004) was also lower in adrenalectomy group. The metaregression showed patient's age may attenuate the benefits of adrenalectomy on composite primary outcomes (coefficient: 1.084 (95% CI: 1.005-1.169), P = 0.036). TSA demonstrated that the accrued sample size and effect size were sufficiently large to draw a solid conclusion, and the advantage of adrenalectomy over MRA was constant with the chronological sequence.

CONCLUSIONS

In conclusion, adrenalectomy could be preferred over MRA for patients with PA in reducing the risk of all-cause mortality and/or MACE and should be considered as the treatment of choice. That patients with PA could get less benefit from adrenalectomy as they age warrants further investigation.

Aldosterone as a Mediator of Cardiovascular Damage

Besides the physiological regulation of water, sodium, and potassium homeostasis, aldosterone modulates several physiological and pathological processes in the cardiovascular system. At the vascular level, aldosterone excess stimulates endothelial dysfunction and infiltration of inflammatory cells, enhances the development of the atherosclerotic plaque, and favors plaque instability, arterial stiffness, and calcification. At the cardiac level, aldosterone increases cardiac inflammation, fibrosis, and myocardial hypertrophy. As a clinical consequence, high aldosterone levels are associated with enhanced risk of cardiovascular events and mortality, especially when aldosterone secretion is inappropriate for renin levels and sodium intake, as in primary aldosteronism. Several clinical trials showed that mineralocorticoid receptor antagonists reduce cardiovascular mortality in patients with heart failure and reduced ejection fraction, but inconclusive results were reported for other cardiovascular conditions, such as heart failure with preserved ejection fraction, myocardial infarction, and atrial fibrillation. In patients with primary aldosteronism, adrenalectomy or treatment with mineralocorticoid receptor antagonists significantly mitigate adverse aldosterone effects, reducing the risk of cardiovascular events, mortality, and incident atrial fibrillation. In this review, we will summarize the major preclinical and clinical studies investigating the cardiovascular damage mediated by aldosterone and the protective effect of mineralocorticoid receptor antagonists for the reduction of cardiovascular risk in patients with cardiovascular diseases and primary aldosteronism.

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.

Primary Aldosteronism and Resistant Hypertension: A Pathophysiological Insight

Primary aldosteronism (PA) is a pathological condition characterized by an excessive aldosterone secretion; once thought to be rare, PA is now recognized as the most common cause of secondary hypertension. Its prevalence increases with the severity of hypertension, reaching up to 29.1% in patients with resistant hypertension (RH). Both PA and RH are "high-risk phenotypes", associated with increased cardiovascular morbidity and mortality compared to non-PA and non-RH patients. Aldosterone excess, as occurs in PA, can contribute to the development of a RH phenotype through several mechanisms. First, inappropriate aldosterone levels with respect to the hydro-electrolytic status of the individual can cause salt retention and volume expansion by inducing sodium and water reabsorption in the kidney. Moreover, a growing body of evidence has highlighted the detrimental consequences of "non-classical" effects of aldosterone in several target tissues. Aldosterone-induced vascular remodeling, sympathetic overactivity, insulin resistance, and adipose tissue dysfunction can further contribute to the worsening of arterial hypertension and to the development of drug-resistance. In addition, the pro-oxidative, pro-fibrotic, and pro-inflammatory effects of aldosterone may aggravate end-organ damage, thereby perpetuating a vicious cycle that eventually leads to a more severe hypertensive phenotype. Finally, neither the pathophysiological mechanisms mediating aldosterone-driven blood pressure rise, nor those mediating aldosterone-driven end-organ damage, are specifically blocked by standard first-line anti-hypertensive drugs, which might further account for the drug-resistant phenotype that frequently characterizes PA patients.

Eplerenone Improves Vascular Endothelial Function in Patients with Primary Aldosteronism: A Pilot Study

Primary aldosteronism (PA) is associated with a high risk of cardiovascular complications. Large-scale clinical studies have demonstrated that mineralocorticoid receptor antagonists (MRA) exhibit organ-protective effects and improve the prognosis of patients with heart failure and myocardial infarction, and daily clinical practice suggests that MRA seem to improve vascular endothelial dysfunction. In this pilot study, we treated 10 PA patients with eplerenone for 3 months. We used Endo-PAT to evaluate the effects of MRA on vascular endothelial function and analyzed the data for correlative factors. The primary outcome measure, the reactive hyperemia index (RHI), was 1.71 before therapy and increased significantly to 2.21. Univariate analysis showed a significant correlation between the rate of change in RHI and that in plasma renin activity (PRA). Since plasma aldosterone concentration increases during MRA therapy, PRA may be the best marker for selecting the most appropriate dose of MRA. PRA can potentially be used for adjusting the dose of MRA, in addition to adjusting blood pressure and serum potassium level.

Immunohistochemical Analysis of CYP11B2, CYP11B1 and β-catenin Helps Subtyping and Relates With Clinical Characteristics of Unilateral Primary Aldosteronism

Background: Primary aldosteronism is caused by aldosterone overproduction. While conventional hematoxylin-eosin staining can demonstrate morphological abnormality, it cannot provide any functional histopathological information. We aimed to identify the diagnostic, functional and prognostic value of CYP11B2, CYP11B1, and β-catenin immunostaining in unilateral hyperaldosteronism.

Method: A total of 134 patients with unilateral hyperaldosteronism were recruited in our study. The expression of CYP11B2, CYP11B1, and β-catenin was evaluated semiquantitatively on 134 patients’ sections using immunohistochemistry technology and the relationship with clinical data was assessed.

Results: Patients were classified into four subtypes based on CYP11B2 staining as below: (1)118 patients with unilateral single aldosterone-producing adenoma (APA), (2)11 with unilateral multiple APA, (3)four with aldosterone-producing cell cluster (APCC), and (4)one with an undefined source. Adjusted CYP11B2 H-score was correlated with serum aldosterone, aldosterone to renin ratio (ARR), and serum potassium. In the abnormal β-catenin staining group, hypertension duration, aldosterone, ARR, cortisol, tumor diameter, tumor area, and CYP11B2 H-score were significantly higher than those of the wild-type group. Serum potassium level was significantly lower in the abnormal β-catenin staining group. Age, gender, BMI, family history of hypertension, adjusted CYP11B2 and CYP11B1 H-scores differed significantly between complete clinical success and incomplete clinical success groups. Age, gender and family history of hypertension were independently associated with complete clinical success based on multivariate logistic regression analysis.

Conclusion: CYP11B2 immunostaining could improve the differential diagnosis of unilateral hyperaldosteronism. Adjusted CYP11B2 H-score could be used as a histopathological marker to reflect the severity of unilateral APA. Dysregulation of Wnt/β-catenin signaling and impaired β-catenin degradation may provoke the proliferation and enhance the steroidogenic ability of APA tumor cells, indicating that the Wnt pathway might be a potential, actionable, therapeutic target in the treatment of hyperaldosteronism. Age, sex and family history of hypertension were independent predictors of clinical outcome after adrenalectomy for unilateral hyperaldosteronism.

Prevalence of primary aldosteronism and association with cardiovascular complications in patients with resistant and refractory hypertension

OBJECTIVES

To assess the prevalence of primary aldosteronism and its association with cardiometabolic complications in patients with resistant and refractory hypertension.

METHODS

One hundred and ten consecutive patients with true resistant hypertension [insufficient blood pressure control despite appropriate lifestyle measures and treatment with at least three classes of antihypertensive medication, including a diuretic] and without previous cardiovascular events were screened for secondary hypertension. Refractory hypertension was diagnosed in case of uncontrolled blood pressure despite the use of at least five antihypertensive drugs.

RESULTS

Primary aldosteronism was diagnosed in 32 cases (29.1%). The multivariate analysis showed that primary aldosteronism is a strong factor positively associated with left ventricular hypertrophy [odds ratio (OR) = 12.98, 95% confidence interval (CI) 3.82-60.88; P < 0.001], microalbuminuria (OR = 3.67, 95% CI 1.44-9.78; P = 0.007), carotid intima-media thickness at least 0.9 mm (OR = 2.69, 95% CI 1.02-7.82; P = 0.037), aortic ectasia (OR = 4.08, 95% CI 1,18-15.04; P = 0.027) and atrial fibrillation (OR 8.80, 95% CI 1.53-73.98; P = 0.022). Moreover, primary aldosteronism was independently associated with the presence of at least one (OR = 8.60, 95% CI 1.73-69.88; P = 0.018) and at least two types of organ damage (OR = 3.08, 95% CI 1.19-8.24; P = 0.022). Thirteen patients (11.8%) were affected by refractory hypertension. This group was characterized by significantly higher values of carotid intima-media thickness, higher rate of aldosterone-producing adenoma and atrial fibrillation, compared with the other individuals with resistant hypertension.

CONCLUSION

The current study indicates that primary aldosteronism is a frequent cause of secondary hypertension and cardiovascular complications among patients with resistant and refractory hypertension, suggesting a crucial role of aldosterone in the pathogenesis of severe hypertensive phenotypes and cardiovascular disease.

Clinical impacts of endothelium-dependent flow-mediated vasodilation assessment on primary aldosteronism

OBJECTIVE

Primary aldosteronism (PA) is divided into two major subtypes, aldosterone-producing adenoma (APA) and bilateral idiopathic hyperplasia (IHA) and is associated with a higher risk of cardiovascular events. However, the nature of vascular function in PA patients remains to be determined. The aim of this study was to determine the vascular function and investigate the implications of vascular function assessments in the patients.

METHODS

Flow-mediated dilation (FMD), as an index of endothelial function, and cardio-ankle vascular index (CAVI), as an index of arterial stiffness, were retrospectively compared between 42 patients with APA, 37 patients with IHA, and 42 patients with essential hypertension (EH). These values were also compared with background factors, KCNJ5 mutation and clinical outcome in terms of blood pressure reduction after adrenalectomy in the APA group.

RESULTS

FMD was significantly lower in the APA group (4.8 ± 2.1%) and IHA group (4.1 ± 1.9%) than in the EH group (5.7 ± 2.1%). CAVI did not differ significantly among groups. Although no significant correlations were seen between FMD and background factors in the IHA group, FMD correlated negatively with BMI and plasma aldosterone concentration in the APA group (rs = -0.313, rs = -0.342, respectively). KCNJ5 mutational status was not associated with FMD value. High FMD was associated with blood pressure normalization after adrenalectomy in the APA group.

CONCLUSIONS

Patients with PA displayed impaired endothelial function. Complete clinical success after adrenalectomy was associated with preserved endothelial function. This study provides a better understanding of FMD assessment in patients with PA.

Comparison of biomarkers of endothelial dysfunction and microvascular endothelial function in patients with primary aldosteronism and essential hypertension

Introduction:

Studies have shown that primary aldosteronism (PA) has a higher risk of cardiovascular events than essential hypertension (EH). Endothelial dysfunction is an independent predictor of cardiovascular events. Whether PA and EH differ in the endothelial dysfunction is uncertain. Our study was designed to investigate the levels of biomarkers of endothelial dysfunction (Asymmetric dimethylarginine, ADMA; E-selectin, and Plasminogen activator inhibitor-1, PAI-1) and assess the microvascular endothelial function in patients with PA and EH, respectively.

Methods:

The biomarkers of endothelial dysfunction were measured by enzyme-linked immunosorbent assay (ELISA). Microvascular endothelial function was evaluated by Pulse amplitude tonometry (PAT).

Results:

Thirty-one subjects with EH and 36 subjects with PA including 22 with aldosterone-producing adenoma (APA) and 14 with idiopathic hyperaldosteronism (IHA) were enrolled in our study. The ADMA levels among the three groups were different (APA 47.83 (27.50, 87.74) ng/ml vs EH 25.08 (22.44, 39.79) ng/ml vs IHA 26.00 (22.23, 33.75) ng/ml; p = 0.04), however, when the APA group was compared with EH and IHA group, there was no statistical significance (47.83 (27.50, 87.74) ng/ml vs 25.08 (22.44, 39.79) ng/ml for EH, p = 0.11; 47.83 (27.50, 87.74) ng/ml vs IHA 26.00 (33.75) ng/ml, p = 0.07). The results of ADMA levels are presented as Median (p25, p75). Whereas, levels of PAI-1 and E-selectin, microvascular endothelial function were not significantly different between PA and EH subjects.

Conclusions:

Our study shows no significant differences between PA and EH in terms of biomarkers of endothelial dysfunction and microvascular endothelial function. The microvascular endothelial function of PA and EH patients is comparable.

Hyperglycemia Potentiates Prothrombotic Effect of Aldosterone in a Rat Arterial Thrombosis Model

We investigated the role of aldosterone (ALDO) in the development of arterial thrombosis in streptozotocin-induced diabetic rats. To evaluate the effect of endogenous ALDO, the rats underwent adrenalectomy (ADX). ADX reduced the development of arterial thrombosis. A 1 h infusion of ALDO (30 μg/kg/h) enhanced thrombosis in adrenalectomized rats, while this effect was potentiated in diabetic rats. ALDO shortened bleeding time, increased plasma levels of tissue factor (TF) and plasminogen activator inhibitor, decreased plasma level of nitric oxide (NO) metabolites, and increased oxidative stress. Moreover, 2 h incubation of human umbilical vein endothelial cells (HUVECs) with ALDO (10^-7 M) disrupted hemostatic balance in endothelial cells in normoglycemia (glucose 5.5 mM), and this effect was more pronounced in hyperglycemia (glucose 30 mM). We demonstrated that the acute ALDO infusion enhances arterial thrombosis in rats and hyperglycemia potentiates this prothrombotic effect. The mechanism of ALDO action was partially mediated by mineralocorticoid (MR) and glucocorticoid (GR) receptors and related to impact of the hormone on primary hemostasis, TF-dependent coagulation cascade, fibrinolysis, NO bioavailability, and oxidative stress balance. Our in vitro study confirmed that ALDO induces prothrombotic phenotype in the endothelium, particularly under hyperglycemic conditions.

Minimally invasive partial versus total adrenalectomy for unilateral primary hyperaldosteronism-a retrospective, multicenter matched-pair analysis using the new international consensus on outcome measures

BACKGROUND

Primary hyperaldosteronism is a recognized risk factor for myocardial infarction, stroke, and atrial fibrillation. Minimally invasive adrenalectomy is the first-line treatment for localized primary hyperaldosteronism. Whether minimally invasive adrenalectomy should be performed using a cortex-sparing technique (partial minimally invasive adrenalectomy) or not (total minimally invasive adrenalectomy) remains a subject of debate. The aim of our study was to evaluate the clinical and biochemical efficacy of both procedures and to examine the morbidity associated with partial minimally invasive adrenalectomy versus total minimally invasive adrenalectomy in a multicenter study.

METHODS

Using a retrospective study design, we determined the efficacy, morbidity, and mortality of partial minimally invasive adrenalectomy and total minimally invasive adrenalectomy. The Primary Aldosteronism Surgical Outcome Study classification was used to explore clinical and biochemical success. Matched-pair analysis was used in order to address possible bias.

RESULTS

We evaluated 234 matched patients with unilateral primary hyperaldosteronism: 78 (33.3%) underwent partial minimally invasive adrenalectomy, and 156 (66.7%) were treated with total minimally invasive adrenalectomy. Complete clinical success was achieved in 40.6%, and partial clinical success in an additional 52.6% of patients in the entire cohort. Complete biochemical success was seen in 94.0% of patients. Success rates and the incidence of perioperative complications were comparable between groups. Both postoperative hypocortisolism (11.5% vs 25.0% after partial minimally invasive adrenalectomy and total minimally invasive adrenalectomy, respectively; P < .001) and postoperative hypoglycemia (2.6% vs 7.1% after partial minimally invasive adrenalectomy and total minimally invasive adrenalectomy; P = .039) occurred more frequently after total minimally invasive adrenalectomy.

CONCLUSION

Our study provides evidence that patients with unilateral primary hyperaldosteronism are good surgical candidates for partial minimally invasive adrenalectomy. Not only is the surgical outcome comparable to that of total minimally invasive adrenalectomy, but also postsurgical morbidity, particularly in terms of hypocortisolism and hypoglycemia, may be reduced.

The aldosterone to renin ratio in the diagnosis of primary aldosteronism: Promises and challenges

The complexity of evaluating patients for secondary treatable causes of hypertension is underappreciated. Primary aldosteronism (PA) is the most prevalent cause of secondary hypertension (3%-32% of hypertensive patients). The recent endocrine society clinical practice guideline (ESCPG), "The Management of Primary Aldosteronism: Case Detection, Diagnosis, and Treatment", differs from the previous version in the explicit recognition of PA as a major public health issue. Despite this, PA is underdiagnosed. The guidelines call on physicians to substantially ramp up the screening of hypertensive patients at risk of PA. Further, it recommends the plasma aldosterone to renin ratio (ARR), as the test of choice for screening for PA. However, the ARR is a highly variable test with reported diagnostic sensitivities and specificities ranging from 66% to 100% and 61% to 100%, respectively. Variability of the ARR can be attributed to the high degree of within-subject variation, differences in sampling protocols, laboratory assays, reporting units, the effect of medications and the population characteristics used to establish the decision thresholds. These factors render the possibility of false positive and false negative results-which have the potential to adversely impact patients. The limitations and caveats to the use of the ARR necessitate an effective clinic-laboratory interface, with specialist physician and clinical scientist collaboration for ARR result interpretation. Improvement in the diagnostic sensitivity and specificity of the ARR is predicated on harmonisation of pretesting patient preparation criteria, knowledge of the analytical methods used to derive the ratio and the method-specific threshold for PA.

Hypertension with primary aldosteronism is associated with increased carotid intima-media thickness and endothelial dysfunction

Patients with primary aldosteronism induced hypertension are more likely to experience cardiovascular events compared to patients with essential hypertension. Primary aldosteronism may therefore have distinct adverse effects on cardiovascular structure and function, independent of hypertension. However, current data on such effects of primary aldosteronism are conflicting. The aim of the present study was to investigate the influence of primary aldosteronism on vascular structure and endothelial function, using intima‐media thickness as a vascular remodeling index and flow‐mediated dilation as a functional parameter. In total, 70 participants were recruited from patients with resistant hypertension. Twenty‐nine patients diagnosed with primary aldosteronism and 41 patients with essential hypertension were prospectively enrolled. Primary aldosteronism was due to aldosterone‐producing adenoma in 10 cases and due to idiopathic adrenal hyperplasia in 19 cases. All patients underwent ultrasound of the common carotid intima‐media thickness and flow‐mediated dilation of the brachial artery. Primary aldosteronism patients had significantly lower flow‐mediated dilation (3.3 [2.4‐7.4] % vs 14.7 [10.3‐19.9] %, P < 0.01) and significantly higher carotid intima‐media thickness (0.9 [0.7‐1.0] mm vs 0.8 [0.6‐0.9] mm, P = 0.02) compared to patients with essential hypertension. These differences remained significant after adjusting for age, sex, diabetes mellitus, 24‐hours systolic blood pressure, and smoking (P < 0.01). No differences in either outcome were observed between the adenoma and adrenal hyperplasia groups (both P > 0.05). Hypertensive patients with hyperaldosteronism appear to exhibit deteriorative effects on both vascular structure and function, independent of hypertension.

Surgical therapy of adrenal tumors: guidelines from the German Association of Endocrine Surgeons (CAEK)

BACKGROUND AND AIMS

Previous guidelines addressing surgery of adrenal tumors required actualization in adaption of developments in the area. The present guideline aims to provide practical and qualified recommendations on an evidence-based level reviewing the prevalent literature for the surgical therapy of adrenal tumors referring to patients of all age groups in operative medicine who require adrenal surgery. It primarily addresses general and visceral surgeons but offers information for all medical doctors related to conservative, ambulatory or inpatient care, rehabilitation, and general practice as well as pediatrics. It extends to interested patients to improve the knowledge and participation in the decision-making process regarding indications and methods of management of adrenal tumors. Furthermore, it provides effective medical options for the surgical treatment of adrenal lesions and balances positive and negative effects. Specific clinical questions addressed refer to indication, diagnostic procedures, effective therapeutic alternatives to surgery, type and extent of surgery, and postoperative management and follow-up regime.

METHODS

A PubMed research using specific key words identified literature to be considered and was evaluated for evidence previous to a formal Delphi decision process that finalized consented recommendations in a multidisciplinary setting.

RESULTS

Overall, 12 general and 52 specific recommendations regarding surgery for adrenal tumors were generated and complementary comments provided.

CONCLUSION

Effective and balanced medical options for the surgical treatment of adrenal tumors are provided on evidence-base. Specific clinical questions regarding indication, diagnostic procedures, alternatives to and type as well as extent of surgery for adrenal tumors including postoperative management are addressed.

Periarterial fat from two human vascular beds is not a source of aldosterone to promote vasoconstriction

Mouse adipocytes have been reported to release aldosterone and reduce endothelium-dependent relaxation. It is unknown whether perivascular adipose tissue (PVAT) releases aldosterone in humans. The present experiments were designed to test the hypothesis that human PVAT releases aldosterone and induces endothelial dysfunction. Vascular reactivity was assessed in human internal mammary and renal segmental arteries obtained at surgery. The arteries were prepared with/without PVAT, and changes in isometric tension were measured in response to the vasoconstrictor thromboxane prostanoid receptor agonist U46619 and the endothelium-dependent vasodilator acetylcholine. The effects of exogenous aldosterone and of mineralocorticoid receptor (MR) antagonist eplerenone were determined. Aldosterone concentrations were measured by ELISA in conditioned media incubated with human adipose tissue with/without angiotensin II stimulation. Presence of aldosterone synthase and MR mRNA was examined in perirenal, abdominal, and mammary PVAT by PCR. U46619 -induced tension and acetylcholine-induced relaxation were unaffected by exogenous and endogenous aldosterone (addition of aldosterone and MR blocker) in mammary and renal segmental arteries, both in the presence and absence of PVAT. Aldosterone release from incubated perivascular fat was not detectable. Aldosterone synthase expression was not consistently observed in human adipose tissues in contrast to that of MR. Thus, exogenous aldosterone does not affect vascular reactivity and endothelial function in ex vivo human arterial segments, and the tested human adipose tissues have no capacity to synthesize/release aldosterone. In perspective, physiologically relevant effects of aldosterone on vascular function in humans are caused by systemic aldosterone originating from the adrenal gland.

Should all Hypertensive Patients be Screened for Primary Aldosteronism?

Primary aldosteronism (PA) is not only a leading cause of secondary and resistant hypertension, but is also quite frequent in unselected hypertensive patients. Moreover, PA is associated with increased cardiovascular risk, which is disproportionate to BP levels. In addition, timely diagnosis of PA and prompt initiation of treatment attenuate this increased risk. On the other hand, there are limited data regarding the usefulness of screening for PA in all asymptomatic or normokalemic hypertensive patients. More importantly, until now, no well-organized, large-scale, prospective, randomized controlled trial has proved the effectiveness of screening for PA for improving clinical outcome. Accordingly, until more relevant data are available, screening for PA should be considered in hypertensive patients with spontaneous or diuretic-induced hypokalemia as well as in those with resistant hypertension. However, screening for PA in all hypertensive patients cannot be currently recommended.

Targeted treatment of primary aldosteronism - The consensus of Taiwan Society of Aldosteronism

BACKGROUND/PURPOSE

Even with the increasing recognition of primary aldosteronism (PA) as a cause of refractory hypertension and an issue of public health, the consensus of its optimal surgical or medical treatment in Taiwan has not been reached. Our objective was to develop a clinical practice guideline that is feasible for real-world management of PA patients in Taiwan.

METHODS

The Taiwan Society of Aldosteronism (TSA) Task Force recognized the above-mentioned issues and reached this Taiwan PA consensus at its inaugural meeting, in order to provide updated information of internationally acceptable standards, and also to incorporate our local disease characteristics and constraints into PA management.

RESULTS

In patients with lateralized PA, including aldosterone producing adenoma (APA), laparoscopic adrenalectomy is the 'gold standard' of treatment. Mini-laparoscopic and laparoendoscopic single-site approaches are feasible only in highly experienced surgeons. Patients with bilateral adrenal hyperplasia or those not suitable for surgery should be treated by mineralocorticoid receptor antagonists. The outcome data of PA patient management from the literature, especially from PA patients in Taiwan, are reviewed. Mental health screening is helpful in early detection and management of psychopathology among PA patients.

CONCLUSION

We hope this consensus will provide a guideline to help medical professionals to manage PA patients in Taiwan to achieve a better quality of care.

Quality of Life in Primary Aldosteronism: A Comparative Effectiveness Study of Adrenalectomy and Medical Treatment

CONTEXT

In primary aldosteronism (PA), two subtypes are distinguished: aldosterone-producing adenoma (APA) and bilateral adrenal hyperplasia (BAH). In general, these are treated by adrenalectomy (ADX) and mineralocorticoid receptor antagonists (MRA), respectively.

OBJECTIVE

To compare the effects of surgical treatment and medical treatment on quality of life (QoL).

DESIGN

Post hoc comparative effectiveness study within the Subtyping Primary Aldosteronism: A Randomized Trial Comparing Adrenal Vein Sampling and Computed Tomography Scan (SPARTACUS) trial.

SETTING

Twelve Dutch hospitals and one Polish hospital.

PARTICIPANTS

Patients with PA (n = 184).

INTERVENTIONS

ADX or MRAs.

MAIN OUTCOME MEASURES

At baseline and 6-month and 1-year follow-up, we assessed QoL by two validated questionnaires: RAND 36-Item Health Survey 1.0 (RAND SF-36) and European Quality of Life-5 Dimensions (EQ-5D).

RESULTS

At baseline, seven of eight RAND SF-36 subscales and both summary scores, as well as three of five EQ-5D dimensions and the visual analog scale, were lower in patients with PA compared with the general population, especially in women. The beneficial effects of ADX were larger than for MRAs for seven RAND SF-36 subscales, both summary scores, and health change. For the EQ-5D, we detected a difference in favor of ADX in two dimensions and the visual analog scale. Most differences in QoL between both treatments exceeded the minimally clinically important difference. After 1 year, almost all QoL measures had normalized for adrenalectomized patients. For patients on medical treatment, most QoL measures had improved but not all to the level of the general population.

CONCLUSION

Both treatments improve QoL in PA, underscoring the importance of identifying these patients. QoL improved more after ADX for suspected APA than after initiation of medical treatment for suspected BAH.

Does Aldosterone Play a Significant Role for Regulation of Vascular Tone?

Besides the well-known renal effects of aldosterone, the hormone is now known to have direct vascular effects. Clinical observations underline substantial adverse effects of aldosterone on cardiovascular function. The source of systemic circulating aldosterone is the adrenal gland zona glomerulosa cells through stimulus-secretion coupling involving depolarization, opening of L- and T-type calcium channels and aldosterone synthase activation. Local formation and release in peripheral tissues such as perivascular fat is recognized. Where does aldosterone affect the vasculature? Mineralocorticoid receptors (MRs) are present in endothelial and vascular smooth muscle cells, and MR-independent pathways are also involved. The vascular effects of aldosterone are complex, both concentration and temporal and spatial aspects are relevant. The acute response includes vasodilation through endothelial nitric oxide formation and vasoconstrictor effects through endothelial-contracting cyclooxygenase-derived factors and a changed calcium handling. The response to aldosterone can change within the same blood vessels depending on the exposure time and status of the endothelium. Chronic responses involve changed levels of reactive oxygen radicals, endothelial Na-influx and smooth muscle calcium channel expression. Furthermore, perivascular cells for example mast cells have also been suggested to participate in the chronic response. Moreover, the vascular effect of aldosterone depends on the status of the endothelium which is likely the cause of the very different responses to aldosterone and MR treatment observed in human studies going from increased to decreased flow depending on whether the patient had prior cardiovascular disease with endothelial dysfunction or not. A preponderance of constrictor versus dilator responses to aldosterone could therefore be involved in the detrimental vascular actions of the hormone in the setting of endothelial dysfunction and contribute to explain the beneficial action of MR blockers on blood pressure and target organ injury.

Primary Aldosteronism: Changing Definitions and New Concepts of Physiology and Pathophysiology Both Inside and Outside the Kidney

In the 60 years that have passed since the discovery of the mineralocorticoid hormone aldosterone, much has been learned about its synthesis (both adrenal and extra-adrenal), regulation (by renin-angiotensin II, potassium, adrenocorticotrophin, and other factors), and effects (on both epithelial and nonepithelial tissues). Once thought to be rare, primary aldosteronism (PA, in which aldosterone secretion by the adrenal is excessive and autonomous of its principal regulator, angiotensin II) is now known to be the most common specifically treatable and potentially curable form of hypertension, with most patients lacking the clinical feature of hypokalemia, the presence of which was previously considered to be necessary to warrant further efforts towards confirming a diagnosis of PA. This, and the appreciation that aldosterone excess leads to adverse cardiovascular, renal, central nervous, and psychological effects, that are at least partly independent of its effects on blood pressure, have had a profound influence on raising clinical and research interest in PA. Such research on patients with PA has, in turn, furthered knowledge regarding aldosterone synthesis, regulation, and effects. This review summarizes current progress in our understanding of the physiology of aldosterone, and towards defining the causes (including genetic bases), epidemiology, outcomes, and clinical approaches to diagnostic workup (including screening, diagnostic confirmation, and subtype differentiation) and treatment of PA.

Hyperaldosteronism and cardiovascular risk in patients with autosomal dominant polycystic kidney disease

Hypertension is commonly associated with autosomal dominant polycystic kidney disease (ADPKD), often discovered before the onset of renal failure, albeit the pathogenetic mechanisms are not well elucidated. Hyperaldosteronism in ADPKD may contribute to the development of insulin resistance and endothelial dysfunction, and progression of cardiorenal disease. The aim of study was to evaluate the prevalence of primary aldosteronism (PA) in ADPKD patients and identify some surrogate biomarkers of cardiovascular risk.We have enrolled 27 hypertensive ADPKD patients with estimated glomerular filtration rate (eGFR) ≥ 60 mL/min, evaluating the renin-angiotensin-aldosterone system (RAAS), inflammatory indexes, nutritional status, homocysteine (Hcy), homeostasis model assessment-insulin resistance (HOMA-IR), mineral metabolism, microalbuminuria, and surrogate markers of atherosclerosis [carotid intima media thickness (cIMT), ankle/brachial index (ABI), flow mediated dilation (FMD), renal resistive index (RRI) and left ventricular mass index (LVMI)]. Furthermore, we have carried out the morpho-functional magnetic resonance imaging (MRI) with high-field 3 T Magnetom Avanto.We have divided patients into group A, with normal plasma aldosterone concentration (PAC) and group B with PA, present in 9 (33%) of overall ADPKD patients. Respect to group A, group B showed a significant higher mean value of LVMI, HOMA-IR and Hcy (P = 0.001, P = 0.004, P = 0.018; respectively), and a lower value of FMD and 25-hydroxyvitamin D (25-OH-VitD) (P = 0.037, P = 0.019; respectively) with a higher prevalence of non-dipper pattern at Ambulatory Blood Pressure Monitoring (ABPM) (65% vs 40%, P < 0.05) at an early stage of the disease.In this study, we showed a high prevalence of PA in ADPKD patients, associated to higher LVMI, HOMA-IR, Hcy, lower FMD, and 25-OH-VitD, considered as surrogate markers of atherosclerosis, compared to ADPKD patients with normal PAC values. Our results indicate a higher overall cardiovascular risk in ADPKD patients with inappropriate aldosterone secretion, and a screening for PA in all patients with ADPKD is recommended.

The Management of Primary Aldosteronism: Case Detection, Diagnosis, and Treatment: An Endocrine Society Clinical Practice Guideline

OBJECTIVE

To develop clinical practice guidelines for the management of patients with primary aldosteronism.

PARTICIPANTS

The Task Force included a chair, selected by the Clinical Guidelines Subcommittee of the Endocrine Society, six additional experts, a methodologist, and a medical writer. The guideline was cosponsored by American Heart Association, American Association of Endocrine Surgeons, European Society of Endocrinology, European Society of Hypertension, International Association of Endocrine Surgeons, International Society of Endocrinology, International Society of Hypertension, Japan Endocrine Society, and The Japanese Society of Hypertension. The Task Force received no corporate funding or remuneration.

EVIDENCE

We searched for systematic reviews and primary studies to formulate the key treatment and prevention recommendations. We used the Grading of Recommendations, Assessment, Development, and Evaluation group criteria to describe both the quality of evidence and the strength of recommendations. We used "recommend" for strong recommendations and "suggest" for weak recommendations.

CONSENSUS PROCESS

We achieved consensus by collecting the best available evidence and conducting one group meeting, several conference calls, and multiple e-mail communications. With the help of a medical writer, the Endocrine Society's Clinical Guidelines Subcommittee, Clinical Affairs Core Committee, and Council successfully reviewed the drafts prepared by the Task Force. We placed the version approved by the Clinical Guidelines Subcommittee and Clinical Affairs Core Committee on the Endocrine Society's website for comments by members. At each stage of review, the Task Force received written comments and incorporated necessary changes.

CONCLUSIONS

For high-risk groups of hypertensive patients and those with hypokalemia, we recommend case detection of primary aldosteronism by determining the aldosterone-renin ratio under standard conditions and recommend that a commonly used confirmatory test should confirm/exclude the condition. We recommend that all patients with primary aldosteronism undergo adrenal computed tomography as the initial study in subtype testing and to exclude adrenocortical carcinoma. We recommend that an experienced radiologist should establish/exclude unilateral primary aldosteronism using bilateral adrenal venous sampling, and if confirmed, this should optimally be treated by laparoscopic adrenalectomy. We recommend that patients with bilateral adrenal hyperplasia or those unsuitable for surgery should be treated primarily with a mineralocorticoid receptor antagonist.

SFE/SFHTA/AFCE consensus on primary aldosteronism, part 1: Epidemiology of PA, who should be screened for sporadic PA?

Depending on the study, the prevalence of primary aldosteronism (PA) in patients with hypertension varies from 6 to 18%. Prevalence is higher in each of the following conditions, any one of which requires screening for PA: severe hypertension (systolic blood pressure [BP]≥180mmHg and/or diastolic BP≥110mmHg); resistant hypertension (systolic BP≥140mmHg and/or diastolic BP≥90mmHg despite adherence to a tritherapy including a thiazide diuretic); hypertension associated with hypokalemia (either spontaneous or associated with a diuretic); Hypertension or hypokalemia associated with adrenal incidentaloma. It should be borne in mind that PA can induce hypertension without hypokalemia or, less frequently, hypokalemia without hypertension. Finally, as cardiovascular and renal morbidity in PA is greater than in essential hypertension of equivalent level, screening for PA is indicated when cardiovascular or renal morbidity is more severe than predicted from BP level.

Time course and factors predicting arterial stiffness reversal in patients with aldosterone-producing adenoma after adrenalectomy: prospective study of 102 patients

Primary aldosteronism not only results in hypertension but also stiffer arteries. The time course and factors predicting the reversal of arterial stiffness after treatment are unclear. We prospectively enrolled 102 patients with aldosterone-producing adenoma (APA) from March 2006 to January 2012. We measured the pulse wave velocity (PWV) between brachial-ankle (baPWV) and heart-ankle (haPWV) before, 6 and 12 months after their adrenalectomy. After treatment, the PWV decreased significantly during the first 6 months (both p < 0.001), but no further reduction in the following 6 months. The determinant factors for baseline baPWV were age, duration of hypertension, and baseline systolic blood pressure (SBP) in multivariate linear regression analysis, similar with baseline haPWV (determinants: age, duration of hypertension, baseline SBP and diastolic blood pressure (DBP)). In multivariate linear regression analysis, the decrease in DBP at 6 months (ΔDBP_0-6mo) and baseline baPWV were significantly associated with the decrease in baPWV at 6 months (ΔbaPWV_0-6mo). The associated factors of the change in haPWV at 6 months (ΔhaPWV_0-6mo) were baseline haPWV, ΔDBP_0-6mo and change in log-transformed plasma renin activity. Our result suggested that reversal of arterial stiffness in APA patients occurred early after adrenalectomy and determined by baseline vascular condition, hemodynamic factors, and humoral factors.

Implication of aortic calcification on persistent hypertension after laparoscopic adrenalectomy in patients with primary aldosteronism

OBJECTIVES

To identify risk factors, including aortic calcification, for persistent hypertension in primary aldosteronism patients undergoing laparoscopic adrenalectomy.

METHODS

Between October 2000 and October 2015, we carried out 101 consecutive laparoscopic adrenalectomies for unilateral primary aldosteronism. Of these, 95 cases with at least 1 year of postoperative follow up were included. These were divided into two study groups based on whether they had normal blood pressure without antihypertensive medications (resolved group) or still required medications (unresolved group) at 1 year after surgery. Variables included age, sex, body mass index, history of hypertension, dosage of antihypertensive medication score, presence of type 2 diabetes, subclinical Cushing syndrome, preoperative renal function, aldosteronoma resolution score and abdominal calcification index. Univariate and multivariate logistic regression analyses were used to assess independent risk factors for persistent hypertension 1 year after surgery.

RESULTS

The complete resolution of hypertension without antihypertensive medication 1 year after adrenalectomy was 36 out of 95 (38%). The preoperative antihypertensive medication score, systolic blood pressure and abdominal calcification index were significantly higher, and the aldosteronoma resolution score were significantly lower in the unresolved group than in the resolved group. Using multivariate logistic regression analysis, independent risk factors significantly correlating with persistent hypertension 1 year after surgery were aldosteronoma resolution score and abdominal calcification index.

CONCLUSIONS

Laparoscopic adrenalectomy for primary aldosteronism is effective in improving blood pressure and reducing the need for antihypertensive medications. Aldosteronoma resolution score and abdominal calcification index represent potential independent risk factors for persistent hypertension 1 year after surgery.

Cardiovascular risk markers in patients with primary aldosteronism: A systematic review and meta-analysis of literature studies

BACKGROUND/OBJECTIVES

Several studies reported an increased cardiovascular (CV) morbidity and mortality in patients with primary aldosteronism (PA). We performed a meta-analysis on the impact of PA on major markers of CV risk.

METHODS

Studies on the relationship between PA and common carotid artery intima-media thickness (CCA-IMT), prevalence of carotid plaques, flow-mediated dilation (FMD), nitrate-mediated dilation (NMD), pulse-wave velocity (PWV), augmentation index (AIx), and ankle-brachial index (ABI) were systematically searched in the PubMed, Web of Science, Scopus and EMBASE databases.

RESULTS

12 case-control studies (445 cases, 472 controls) were included. Compared to subjects with essential hypertension (EH), PA patients showed a higher CCA-IMT (MD: 0.12 mm; 95% CI: 0.09, 0.16; P<0.00001), and a higher aortic-PWV (272 cases and 240 controls, MD: 1.39 m/s; 95% CI: 0.90, 1.87; P<0.00001). In contrast, non-significant differences were found in AIx and AIx normalized to a heart rate of 75 beats per minute (AIx@75). When compared to normotensive subjects, PA patients showed significantly higher CCA-IMT (MD: 0.16 mm; 95% CI: 0.05, 0.27; P=0.004), aortic-PWV (MD: 3.74 m/s; 95% CI: 3.43, 4.05; P<0.00001), AIx@75 (MD: 8.59%; 95% CI: 0.69, 16.50; P=0.03), and a significantly lower FMD (MD: -2.52%; 95% CI: -3.64, -1.40; P<0.0001). Sensitivity and subgroup analyses substantially confirmed our results. Metaregression models showed that male gender, diabetes, and smoking habit impact on the observed results.

CONCLUSIONS

PA appears significantly associated with markers of subclinical atherosclerosis and CV risk. These findings could help establish more specific CV prevention strategies in this clinical setting.

Eplerenone improves carotid intima-media thickness (IMT) in patients with primary aldosteronism

Primary aldosteronism (PA) is associated with a higher rate of cardiovascular events than essential hypertension. Although adrenalectomy has been reported to reduce carotid intima-media thickness (IMT) in patients with PA, the effects of the selective aldosterone blocker, eplerenone, on vascular damage in these patients remains unclear. To evaluate the effects of eplerenone on vascular status in PA patients, we sequentially measured carotid IMT (using computer software to calculate an average IMT for accurate and reproducible evaluation) in 22 patients including 8 patients treated by unilateral adrenalectomy and 14 patients treated with eplerenone for 12 months. Patients who underwent adrenalectomy showed significant reductions in aldosterone concentration (from 345 ± 176 pg/mL to 67 ± 34 pg/mL; P<0.01) and IMT (from 0.67 ± 0.07 mm to 0.63 ± 0.09 mm; P<0.05) 6 months after surgery. Patients treated with eplerenone showed significant reductions in IMT from baseline (0.75 ± 0.10 mm) to 6 (0.71 ± 0.11 mm; P<0.05) and 12 (0.65 ± 0.09 mm; P<0.01) months, although plasma aldosterone level increased significantly, from 141 ± 105 pg/mL to 207 ± 98 pg/mL (P<0.05). Eplerenone treatment of patients with PA reduces blood pressure, increases serum potassium level, and improves vascular status. Carotid IMT may be a useful marker for evaluating the effectiveness of eplerenone in patients with PA.

Endothelial dysfunction in patients with primary aldosteronism: a biomarker of target organ damage

Primary aldosteronism (PA) has been associated with increased target organ damage (TOD), most likely through mineralocorticoid receptor-dependent endothelial dysfunction, in comparison with essential hypertension (EH). The aim of this study was to evaluate the level of biomarkers of endothelial dysfunction in PA and the relationship with left ventricular hypertrophy (LVH) and microalbuminuria (MAU). A total of 50 PA patients and 51 patients with EH individually matched for age, sex, blood pressure and duration of hypertension participated in this study. Biomarkers of endothelial dysfunction, including von Willebrand factor (vWF), intercellular adhesion molecule 1 (ICAM-1) and oxidized low-density lipoprotein (ox-LDL), were measured. Plasma aldosterone concentration (PAC), MAU and echocardiography were also evaluated. In PA patients, vWF, ICAM-1, ox-LDL, LVH and MAU were all significantly higher than in EH patients (all P<0.05). Furthermore, LVH was positively correlated with PAC (P=0.002), vWF (P=0.013) and ox-LDL (P=0.020). MAU was positively correlated with PAC (P<0.001), vWF (P=0.013) and ICAM-1 (P=0.001). Multiple regression analysis indicated that vWF, ICAM-1 and PAC independently predicted MAU (all P<0.05). Likewise, PAC, vWF and ox-LDL were significant predictors of LVH (all P<0.05). Taken together, our results suggest that endothelial dysfunction may contribute to TOD in PA patients.

Aldosterone affects blood flow and vascular tone regulated by endothelium-derived NO: therapeutic implications

Aldosterone, in doses inappropriate to the salt status, plays an important role in the development of cardiovascular injury, including endothelial dysfunction, independent of its hypertensive effects. Acute non-genomic effects of aldosterone acting on mineralocorticoid receptors are inconsistent in healthy humans: vasoconstriction or forearm blood flow decrease via endothelial dysfunction, vasodilatation mediated by increased NO actions, or no effects. However, in studies with experimental animals, aldosterone mostly enhances vasodilatation mediated by endothelium-derived NO. Chronic exposure to aldosterone, which induces genomic responses, results in impairments of endothelial function through decreased NO synthesis and action in healthy individuals, experimental animals and isolated endothelial cells. Chronic aldosterone reduces NO release from isolated human endothelial cells only when extracellular sodium is raised. Oxidative stress is involved in the impairment of endothelial function by promoting NO degradation. Aldosterone liberates endothelin-1 (ET-1) from endothelial cells, which elicits ET(A) receptor-mediated vasoconstriction by inhibiting endothelial NO synthesis and action and through its own direct vasoconstrictor action. Ca(2+) flux through T-type Ca(2+) channels activates aldosterone synthesis and thus enhances unwanted effects of aldosterone on the endothelium. Mineralocorticoid receptor inhibitors, ET(A) receptor antagonists and T-type Ca(2) + channel blockers appear to diminish the pathophysiological participation of aldosterone in cardiovascular disease and exert beneficial actions on bioavailability of endothelium-derived NO, particularly in resistant hypertension and aldosteronism.

Renin is activated in monochorionic diamniotic twins with birthweight discordance who do not have twin-to-twin transfusion syndrome

OBJECTIVE

To assess renin, aldosterone, human atrial natriuretic peptide (hANP) and brain natriuretic peptide (BNP) levels in cord blood from monochorionic diamniotic (MD) twins with a birthweight (BW) discordance that do not satisfy the criteria of twin-to-twin transfusion syndrome (TTTS).

STUDY DESIGN

Cord blood samples were obtained from 28 MD twins without TTTS. They were divided into two groups on the basis of BW discordance as follows: large (>7.5%) and small (7.5%). Cord blood renin, aldosterone, hANP and BNP levels were measured.

RESULT

Renin levels in MD twins with a large BW discordance were significantly higher than those in MD twins with a small BW discordance, with no significant differences in aldosterone, hANP and BNP levels. A significant correlation was found between renin levels and BW discordance.

CONCLUSION

Renin is activated in MD twins with a BW discordance of >7.5%, even in non-TTTS.

Resistant hypertension and aldosterone: an update

Resistant hypertension (RHTN) is defined as a blood pressure remaining above goal despite the concurrent use of 3 antihypertensive medications of different classes, including, ideally a diuretic. RHTN is an important health problem with a prevalence rate expected to increase as populations become older, more obese, and at higher risk of having diabetes and chronic kidney disease, all of which are important risk factors for development of RHTN. The role of aldosterone has gained increasing recognition as a significant contributor to antihypertensive treatment resistance. In prospective studies, the prevalence of primary aldosteronism (PA) has ranged from 14%-21% in patients with RHTN, which is considerably higher than in the general hypertensive population. Furthermore, marked antihypertensive effects are seen when mineralocorticoid antagonists are added to the treatment regimen of patients with RHTN, further supporting aldosterone excess as an important cause of RHTN. A close association exists between hyperaldosteronism, RHTN, and obstructive sleep apnea (OSA) based upon recent studies which indicate that OSA is worsened by aldosterone-mediated fluid retention. This interaction is supported by preliminary data which demonstrates improvement in OSA severity after treatment with spironolactone.

Plasma aldosterone levels and aldosterone-to-renin ratios are associated with endothelial dysfunction in young to middle-aged subjects

OBJECTIVE

Small clinical studies suggested a role for aldosterone in the development of endothelial dysfunction. We investigated whether the plasma aldosterone concentration (PAC) or the aldosterone-to-renin ratio (ARR) were associated with decreased endothelial function as measured by flow-mediated dilation (FMD) of the brachial artery in the general population.

METHODS

Our study population comprised 972 participants from the Study of Health in Pomerania, who were not treated with antihypertensive medication. We performed age-stratified (<50 and ≥ 50 years) ordinal logistic regression analyses. FMD was categorised as decreased (1st quintile), moderate (2nd-4th quintile), or increased (5th quintile). PAC and ARR were divided into low, moderate, and high values according to age- and sex-specific tertiles. All models were re-calculated for 871 subjects with PAC and ARR within the study-specific reference ranges. Odds ratios (OR) and 95% confidence intervals (CI) are presented.

RESULTS

Subjects <50 years with high PAC (OR 1.60; 95% CI 1.07-2.38) or ARR (OR 1.81; 95% CI 1.21-2.73) had higher odds for decreased FMD than subjects with low PAC or ARR, respectively. Similar results were obtained in analyses restricted to subjects with PAC and ARR within the reference range. High-normal PAC (OR 1.62; 95% CI 1.07-2.47) or ARR (OR 1.62; 95% CI 1.05-2.50) was associated with higher odds for decreased FMD when compared with low-normal PAC or ARR, respectively. These associations were not observed in subjects ≥ 50 years.

CONCLUSIONS

High and high-normal PAC or ARR contribute to an impaired FMD and subsequently the progression of subclinical atherosclerosis in young to middle-aged subjects.

Effects of carbenoxolone on flow-mediated vasodilatation in healthy adults

Gap junctions play a key role in maintaining the functional integrity of the vascular wall. Using carbenoxolone (CBX) as a gap junction blocker, we aimed to assess the contribution of gap junctions in the vascular wall to flow-mediated vasodilatation (FMD) in healthy adults. Percentage FMD (%FMD) and circulating vasoactive molecules/activity, including atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), aldosterone, cortisol, plasma renin activity (PRA), and endothelin (ET-1), were measured in 25 healthy volunteers (mean age: 30.1 ± 5.4 yr; 14 males) before and after oral administration of CBX (100 mg). %FMD decreased after ingestion of CBX (9.71 ± 3.1 vs. 3.40 ± 2.0%; P < 0.0001). The levels of ANP, BNP, cortisol, and ET-1 remained stationary, while both PRA and aldosterone decreased ( P < 0.005) after CBX ingestion. Blood pressure and heart rate were minimally changed by CBX. Inhibition of gap junctional communication by CBX impairs FMD in healthy persons, suggesting that physiologically, vascular gap junctions participate in the maintenance of FMD. CBX does not induce the release of vasoconstricting molecules or enhance vasoconstriction, suggesting that inhibition of gap junctional communication by CBX underlies the impairment of FMD. Therefore, administering CBX in FMD examination can be a way to follow the effect of gap junctions on endothelial function, but further work remains to verify the specificity of CBX effect.

Vascular endothelial function and hypertension: insights and directions

Hypertension contributes significantly to worldwide cardiovascular morbidity and mortality. Hypertension appears to have a complex association with endothelial dysfunction, a phenotypical alteration of the vascular endothelium that precedes the development of adverse cardiovascular events and portends future cardiovascular risk. This review concentrates on recent findings with respect to the mechanisms of hypertension-associated endothelial dysfunction, the interrelationship between these two entities, and the relationship of the efficacy of antihypertensive therapies to improvements in vascular homeostasis beyond blood pressure reduction. Current evidence suggests that hypertension and endothelial dysfunction are integrally related with respect to pathophysiologic mechanisms. Future studies will need to identify the key connections between hypertension and endothelial dysfunction to allow novel interventions to be designed and promulgated.

Treatment of primary aldosteronism: Where are we now?

Primary aldosteronism (PA) is an important cause of secondary hypertension, is being increasingly diagnosed and may account for more than 10% of hypertensive patients, both in primary care and in referral centers. Aldosterone excess is associated with adverse cardiovascular, renal and metabolic effects that are in part hypertension-independent. Laparoscopic adrenalectomy remains the mainstay of treatment for unilateral forms of PA, whereas medical treatment is recommended for bilateral forms of PA. However, a favourable surgical outcome depends on several factors and many patients are not suitable for this treatment. On the other hand, surgery in patients considered to have bilateral PA may contribute to better blood pressure control. In this review, established and novel strategies for the management of different types of PA are discussed.

Aldosteronism and resistant hypertension

Resistant hypertension (RHTN) is defined as blood pressure (BP) that remains uncontrolled in spite of intake of ≥3 antihypertensive medications, ideally prescribed at optimal doses and one of which is a diuretic. The incidence of primary aldosteronism (PA) in patients with RHTN is estimated in prospective studies to be 14 to 23%, which is higher than in the general hypertensive population. Patients with PA are at an increased cardiovascular risk, as shown by higher rates of stroke, myocardial infarction, and arrhythmias compared to hypertensive individuals without PA. Likewise, RHTN is associated with adverse cardiovascular outcomes, and the contribution of PA to this increased risk is undetermined. Similar to PA, obstructive sleep apnea (OSA) is closely associated with RHTN, and a causal link between PA, OSA, and RHTN remains to be elucidated. The addition of MR antagonists to the antihypertensive regimen in patients with RHTN produces a profound BP-lowering effect, and this effect is seen in patients with or without biochemical evidence of PA, highlighting the role of relative aldosterone excess in driving treatment resistance in this group of patients.

Update in primary aldosteronism

It is now widely recognized that primary aldosteronism (PA) is much more common than previously thought, accounting for up to 5-10% of hypertensives, and that aldosterone excess has adverse cardiovascular consequences that go above and beyond hypertension development. These findings have precipitated a marked resurgence of research activity, most of which has supported the concept that PA plays an important role in cardiovascular disease states and should be systematically sought and specifically treated, and the development of an Endocrine Society clinical guideline for the case detection, diagnosis, and management of this common, specifically treatable, and potentially curable condition. Areas of recent, topical research include: 1) the demonstration of excess morbidity in patients with PA compared with other forms of hypertension, confirming the clinical relevance of non-blood pressure-dependent adverse effects of aldosterone excess; 2) the further demonstration that this excess morbidity and mortality are ameliorated with specific (but not nonspecific antihypertensive) therapy directed against aldosterone excess, confirming the importance of detection and diagnosis of PA to enable optimal specific management; 3) the development of new treatment strategies; 4) an ongoing appraisal and refinement of diagnostic approaches including screening, subtype differentiation, and new assay development; and 5) further insights into the importance and nature of genetic factors related to the development of PA.