Aldosterone as a cardiovascular risk factor

High prevalence of primary aldosteronism in a tertiary care hospital in Lebanon

Primary aldosteronism (PA) is a frequent cause of secondary hypertension. Studies on the prevalence of PA are lacking in the Middle East region. To determine the proportion of patients with high aldosterone-to-renin ratio (ARR) among Lebanese patients with hypertension screened for PA and to compare their clinical and biological characteristics with patients with essential hypertension. A retrospective review of medical charts of patients with hypertension undergoing sampling of serum aldosterone and plasma renin concentration at a tertiary care center between October 2022 and 2023 was conducted. Of 144 patients with hypertension screened for PA, 23 (16%) had an ARR higher than 3.7 ng/dL/mU/L and serum aldosterone above 15 ng/dL. The mean age of the screened population was 51 ± 15 years, 56% were men. The median duration of hypertension was 4 years and the median number was 2 of antihypertensive medications. Patients with a positive screening test were mostly men (88%, P = .0001), and more frequently had diabetes (50%, P < .0001) than those with essential hypertension. Only 22% had hypokalemia. Of the 23 patients, 11 underwent intravenous saline suppression testing; PA was confirmed in all of them. The high frequency of PA in our center is comparable to other countries. More studies are needed to determine how to reduce healthcare disparities and overcome the barriers to appropriate diagnosis and treatment.

Circulating miRNAs and Machine Learning for Lateralizing Primary Aldosteronism

BACKGROUND

Distinguishing between unilateral and bilateral primary aldosteronism, a major cause of secondary hypertension, is crucial due to different treatment approaches. While adrenal venous sampling is the gold standard, its invasiveness, limited availability, and often difficult interpretation pose challenges. This study explores the utility of circulating microRNAs (miRNAs) and machine learning in distinguishing between unilateral and bilateral forms of primary aldosteronism.

METHODS

MiRNA profiling was conducted on plasma samples from 18 patients with primary aldosteronism taken during adrenal venous sampling on an Illumina MiSeq platform. Bioinformatics and machine learning identified 9 miRNAs for validation by reverse transcription real-time quantitative polymerase chain reaction. Validation was performed on a cohort consisting of 108 patients with known subdifferentiation. A 30-patient subset of the validation cohort involved both adrenal venous sampling and peripheral, the rest only peripheral samples. A neural network model was used for feature selection and comparison between adrenal venous sampling and peripheral samples, while a deep-learning model was used for classification.

RESULTS

Our model identified 10 miRNA combinations achieving >85% accuracy in distinguishing unilateral primary aldosteronism and bilateral adrenal hyperplasia on a 30-sample subset, while also confirming the suitability of peripheral samples for analysis. The best model, involving 6 miRNAs, achieved an area under curve of 87.1%. Deep learning resulted in 100% accuracy on the subset and 90.9% sensitivity and 81.8% specificity on all 108 samples, with an area under curve of 86.7%.

CONCLUSIONS

Machine learning analysis of circulating miRNAs offers a minimally invasive alternative for primary aldosteronism lateralization. Early identification of bilateral adrenal hyperplasia could expedite treatment initiation without the need for further localization, benefiting both patients and health care providers.

A bibliometric and visualization analysis of global trends and frontiers on macrophages in abdominal aortic aneurysms research

BACKGROUND

Macrophages are key regulators of the inflammatory and innate immune responses. Researchers have shown that aberrant expression of macrophages contributes to the development of abdominal aortic aneurysms (AAA). However, a comprehensive bibliometric analysis exploring the research status and knowledge mapping of this area is lacking. This study aimed to explore the research status, knowledge mapping and hotspots of macrophages in AAA research from a bibliometric perspective.

METHODS

In this study, we retrieved articles published between 2000 and 2022 on macrophages associated with AAA research from the Web of Science Core Collection (WoSCC) database. The retrieved literature data were further analyzed using Citespace and VOSviewer software.

RESULTS

A total of 918 qualified publications related to AAA-associated macrophages were retrieved. The number of publications in this field has been increasing annually. China and the United States were the 2 main drivers in this field, contributing to more than 64% of the publications. In addition, the US had the most publications, top institutions, and expert researchers, dominating in research on macrophages in AAA. The Harvard University was the most productive institution, with 60 publications. The journal with the most publications was Arteriosclerosis, Thrombosis, and Vascular Biology (86). Daugherty Alan was the most prolific author (28 publications) and he was also the most cited co- author. Furthermore, the exploration of established animal models, macrophage-related inflammatory-microenvironment, macrophage-related immune mechanism, clinical translation and molecular imaging research remained future research directions in this field.

CONCLUSIONS

Our findings offered new insights for scholars in this field. They will help researchers explore new directions for their work.

The influence of cortisol co-secretion on clinical characteristics and postoperative outcomes in unilateral primary aldosteronism

Context

The prevalence of unilateral primary aldosteronism (UPA) with cortisol co-secretion varies geographically.

Objective

To investigate the prevalence and clinical characteristics of UPA with cortisol co-secretion in a Chinese population.

Design

Retrospective cohort study.

Methods

We recruited 580 patients with UPA who underwent cosyntropin stimulation test (CST) after the 1-mg dexamethasone suppression test (DST) and retrospectively analyzed the clinical characteristics and postoperative outcomes of UPA with and without cortisol co-secretion.

Results

UPA with cortisol co-secretion (1 mg DST>1.8 ug/dL) was identified in 65 of 580 (11.2%) patients. These patients were characterized by older age, longer duration of hypertension, higher concentration of plasma aldosterone and midnight cortisol, lower adrenocorticotropic hormone (ACTH) and dehydroepiandrosterone sulfate (DHEAS), larger tumor diameter, and more history of diabetes mellitus. Cortisol and aldosterone levels were higher and DHEAS level was lower in UPA with cortisol co-secretion at 0-120 min after CST. Among 342 UPA patients with KCNJ5 gene sequencing and follow-up results, the complete clinical success rate was lower in UPA with cortisol co-secretion (33.3% vs. 56.4%, P<0.05); the complete biochemical success rate and KCNJ5 mutation did not differ between the two groups. Age, tumor size, and ACTH were independent predictors of UPA with cortisol co-secretion. Sex, BMI, duration of hypertension, KCNJ5 mutation, and cortisol co-secretion were independent predictors for complete clinical success in UPA after surgery.

Conclusions

UPA with cortisol co-secretion is not uncommon in China, but the clinical features were distinctly different from those without co-secretion. Cortisol co-secretion is an independent risk factor for incomplete clinical success after surgery in UPA.

UPLC-MS based metabonomics revealed the protective effects of Buyang Huanwu decoction on ischemic stroke rats

Objective

Storke is a leading cause of death and disability affecting million people worldwide, 80% of which is ischemic stroke (IS). Recently, traditional Chinese medicines (TCMs) have received great attentions in treating IS due to their low poisonous effects and high safety. Buyang Huanwu Decoction (BHD), a famous and classical Chinese prescription, has been used for treating stroke-induced disability for centuries. Yet, its underlying mechanism is still in fancy.

Methods

We first constructed an IS model by middle cerebral artery occlusion (MCAO). Then, a metabonomics study on serum samples was performed using UHPLC-QTOF/MS, followed by multivariate data analysis including principal components analysis (PCA) and orthogonal partial least squares-discriminate analysis (OPLS-DA).

Results

Metabolic profiling of PCA indicated metabolic perturbation caused by MCAO was regulated by BHD back to normal levels, which is in agreement with the neurobehavioral evaluations. In the OPLS-DA, 12 metabolites were screened as potential biomarkers involved in MCAO-induced IS. Three metabolic pathways were recognized as the most relevant pathways, involving one carbon pool by folate, sphingolipid metabolism and inositol phosphate metabolism. BHD significantly reversed the abnormality of 7 metabolites to normal levels.

Conclusions

This is the first study to investigate the effect of BHD on IS at the metabolite level and to reveal the underlying mechanisms of BHD, which is complementary to neurobehavioral evaluation. In a broad sense, the current study brings novel and valuable insights to evaluate efficacy of TCMs, to interpret the action mechanisms, and to provide the theoretical basis for further research on the therapeutic mechanisms in clinical practice.

Association of the trajectory of plasma aldosterone concentration with the risk of cardiovascular disease in patients with hypertension: a cohort study

The purpose of this study was to determine the long-term pattern of plasma aldosterone concentration (PAC) trajectories and to explore the relationship between PAC trajectory patterns and cardiovascular disease (CVD) risk in patients with hypertension. Participants were surveyed three times between 2010 and 2016, and latent mixed modeling was employed to determine the trajectory of PAC over the exposure period (2010-2016). A Cox regression analysis was used to examine the association between PAC trajectory patterns and the risk of CVD (stroke and myocardial infarction). Hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) were calculated and reported. During a median follow-up of 4.10 (3.37-4.50) years, 82 incident CVD cases (33 myocardial infarction cases and 49 stroke cases) were identified. Among all three PAC models, the high-stability PAC pattern exhibited the highest risk of CVD. After full adjustment for all covariables, HRs were 2.19 (95% CI 1.59-3.01) for the moderate-stable pattern and 2.56 (95% CI 1.68-3.91) for the high-stable pattern in comparison to the low-stable pattern. Subgroup and sensitivity analyses verified this association. The presence of a high-stable PAC trajectory pattern is associated with an elevated risk of CVD in hypertensive patients. Nevertheless, more studies are warranted to confirm these findings.

Influence of cortisol cosecretion on non-ACTH-stimulated adrenal venous sampling in primary aldosteronism: a retrospective cohort study

OBJECTIVE

Cortisol measurements are essential for the interpretation of adrenal venous samplings (AVS) in primary aldosteronism (PA). Cortisol cosecretion may influence AVS indices. We aimed to investigate whether cortisol cosecretion affects non-adrenocorticotrophic hormone (ACTH)-stimulated AVS results.

DESIGN

Retrospective cohort study at a tertiary referral center.

METHODS

We analyzed 278 PA patients who underwent non-ACTH-stimulated AVS and had undergone at least a 1-mg dexamethasone suppression test (DST). Subsets underwent additional late-night salivary cortisol (LSC) and/or 24-h urinary free cortisol (UFC) measurements. Patients were studied from 2013 to 2020 with follow-up data of 6 months following adrenalectomy or mineralocorticoid antagonist therapy initiation. We analyzed AVS parameters including adrenal vein aldosterone/cortisol ratios, selectivity, lateralization (LI) and contralateral suppression indices and post-operative ACTH-stimulation. We classified outcomes according to the primary aldosteronism surgical outcome (PASO) criteria.

RESULTS

Among the patients, 18.9% had a pathological DST result (1.9-5 µg/dL: n = 44 (15.8%); >5 µg/dL: n = 8 (2.9%)). Comparison of AVS results stratified according to the 1-mg DST (≤1.8 vs >1.8 µg/dL: P = 0.499; ≤1.8 vs 1.8 ≤ 5 vs >5 µg/dL: P = 0.811) showed no difference. Lateralized cases with post DST serum cortisol values > 5 µg/dL had lower LI (≤1.8 µg/dL: 11.11 (5.36; 26.76) vs 1.9-5 µg/dL: 11.76 (4.9; 31.88) vs >5 µg/dL: 2.58 (1.67; 3.3); P = 0.008). PASO outcome was not different according to cortisol cosecretion.

CONCLUSIONS

Marked cortisol cosecretion has the potential to influence non-ACTH-stimulated AVS results. While this could result in falsely classified lateralized cases as bilateral, further analysis of substitutes for cortisol are required to unmask effects on clinical outcome.

Adrenal Vein Sampling in a Patient With Primary Hyperaldosteronism and Severe Contrast Allergy

We report on a case of a 50-year-old female patient with primary hyperaldosteronism, in whom adrenal venous sampling was required to differentiate between unilateral and bilateral disease. Because of a history of severe allergy to iodinated contrast media, premedication with glucocorticoids was indicated. Exogenous glucocorticoids, however, can affect measurements of serum cortisol. To avoid this potential confounding effects on the cortisol assay, we decided to use dexamethasone instead of prednisolone or hydrocortisone. A high-dose adrenocorticotropin (ACTH) stimulation test with the simultaneous use of dexamethasone revealed an adequate adrenal cortisol response. ACTH-stimulated adrenal venous sampling showed reliable results, which provided a solid basis for further clinical decision-making.

Higher risk of chronic kidney disease and progressive kidney function impairment in primary aldosteronism than in essential hypertension. Case-control study

PURPOSE

To study the differences in the prevalence, risk, and grade of control of different cardiometabolic comorbidities in patients with primary aldosteronism (PA) and essential hypertension (EH) matched by age, sex, and blood pressure levels at diagnosis.

METHODS

Case-control study of a secondary base (PA patients in follow-up in a tertiary hospital between 2018 and 2020). Controls were patients with non-functioning adrenal incidentalomas and EH, matched by age, sex, and baseline diastolic blood pressure (DBP) and systolic blood pressure (SBP).

RESULTS

Fifty patients with PA and 50 controls were enrolled in the study. At diagnosis, PA patients had a higher prevalence of chronic kidney disease (CKD) than controls (18.4% vs. 2.1%, P = 0.008). No differences were detected in the prevalence of other cardiometabolic comorbidities nor in their degree of control (P > 0.05). All patients received antihypertensive medical treatment and 10 PA patients underwent unilateral laparoscopic adrenalectomy. After a median follow-up of 31.9 [IQR = 1.0-254.8] months, PA patients presented a greater degree of declination of kidney function than controls (average decrease in glomerular filtration rate (MDRD-4) -17.6 ± 3.1 vs. -2.8 ± 1.8 ml/min/1.73 m², P < 0.001). There were no differences in the grade of SBP (P = 0.840) and DBP control (P = 0.191), nor in the risk of developing other comorbidities or in their degree of control.

CONCLUSIONS

PA patients have a higher prevalence of CKD at the time of diagnosis when compared to EH matched by age, sex, and blood pressure levels. Furthermore, the risk of kidney function impairment throughout the follow-up is significantly greater in PA patients and is independent of the degree of blood pressure control.

Cardiovascular events and all-cause mortality in surgically or medically treated primary aldosteronism: A Meta-analysis

Objectives:

To compare the effect of surgical or medical treatment on the risk of cardiovascular diseases (CVD) and all-cause mortality in patients with established primary aldosteronism (PA).

Methods:

We searched PUBMED, MEDLINE and Cochrane Library for the meta-analysis. We included patients who were diagnosed with PA following guideline-supported protocols and received surgery or mineralocorticoid receptor antagonist (MRA)-based medical treatment, and age-sex matched patients with treated essential hypertension (EH). Primary endpoints were CVD incidence and all-cause mortality.

Results:

Compared with EH, patients with treated PA had a higher risk of CVD [odds ratio (OR) 1.79; 95% confidence interval (CI) 1.39–2.31]. This elevated risk was only observed in patients with medically treated PA [OR 2.11; 95%CI 1.88–2.38] but not in those with surgically treated PA. The risk of all-cause mortality was significantly lower in patients with treated PA [OR 0.86; 95% CI 0.77–0.95] compared to EH. The reduced risk was only observed in patients with surgically treated PA [OR 0.47; 95% CI 0.34–0.66], but not in those with medically treated PA.

Conclusions:

Patients with medically treated PA have a higher risk of CVD compared to patients with EH. Surgical treatment of PA reduces the risk of CVD and all-cause mortality in patients with PA.

Protective effect of inhibiting TRPM7 expression on hypoxia post-treatment H9C2 cardiomyocytes

BACKGROUND

Transient receptor potential channel 7 (TRPM7) plays an important role in maintaining intracellular ion concentration and osmotic pressure.

OBJECTIVE

The purpose of this study was to investigate the role and mechanism of inhibiting the expression of TRPM7 in the treatment of distal myocardial ischemia.

METHODS

H9C2 cells were treated with hypoxia post-treatment and reperfusion, respectively, detect the expression of HIF-1α and TRPM7, the concentration of Ca2+ and the degree of apoptosis in the H9C2 cells. The relevant miRNAs targeting TRPM7 were searched, the TRPM7 interference vectors were constructed, and the interference of different interference vectors on TRPM7 in H9C2 cells was detected.

RESULTS

The results showed that hypoxia post-treatment treatment would lead to increased expression of miR-22-3p which directly targeting TRPM7, decreased expression of TRPM7, increased expression of HIF-α and increased intracellular Ca2+ concentration. While reperfusion can increase the expression of HIF-1α and TRPM7 in H9C2 cells and increase the degree of apoptosis.

CONCLUSION

Knockdown of TRPM7 can significantly reduce reperfusion injury in H9C2 cells, reduce the degree of apoptosis, and the TRPM7 interference vector can inhibit the expression of TRPM7 and have a certain protective effect on the reperfusion injury of H9C2 cells.

Primary Aldosteronism: JACC State-of-the-Art Review

Primary aldosteronism (PA) is a common, but frequently overlooked, cause of arterial hypertension and excess cardiovascular events, particularly atrial fibrillation. As timely diagnosis and treatment can provide a cure of hyperaldosteronism and hypertension, even when the latter is resistant to drug treatment, strategies to screen patients for PA early with a simplified diagnostic algorithm are justified. They can be particularly beneficial in some subgroups of hypertensive patients, as those who are at highest cardiovascular risk. However, identification of the surgically curable cases of PA and achievement of optimal results require subtyping with adrenal vein sampling, which, as it is technically challenging and currently performed only in tertiary referral centers, represents the bottleneck in the work-up of PA. Measures aimed at improving the clinical use of adrenal vein sampling and at developing alternative techniques for subtyping, alongside recommendations for drug treatment, including new development in the field, and for follow-up are discussed.

Disease monitoring of Primary Aldosteronism

Primary aldosteronism (PA) is a highly prevalent cause of arterial hypertension featuring excess cardiovascular events. A timely diagnosis and treatment of PA cures hyperaldosteronism and can provide resolution or improvement of arterial hypertension, even when the latter is resistant to drug treatment. Accordingly, strategies to screen early and widely the hypertensive patients for PA by means of simplified diagnostic algorithms are justified. Such strategies are particularly beneficial in subgroups of hypertensive patients, who are at the highest cardiovascular risk. Broadening of screening strategies means facing with an increased number of patients where monitoring the disease becomes necessary. Hence, after identification of the surgically and non surgically curable cases of PA and implementation of targeted treatment physicians are faced with the challenges of follow-up, which are scantly discussed in the literature. Hence, the purpose of this paper is to provide some recommendations on how to optimize the monitoring of patients in whom the PA subtype has been diagnosed and treatment, either with unilateral laparoscopic adrenalectomy or medically, has been instituted.

Incidence of Acute Kidney Injury after Adrenalectomy in Patients with Primary Aldosteronism

Background

Aldosterone-induced glomerular hyperfiltration can lead to masked preoperative renal dysfunction in primary aldosteronism(PA) patients. We evaluated whether PA patients had a higher prevalence of acute kidney injury (AKI) after unilateral adrenalectomy. In addition, we identified risk factors for AKI in these subjects.

Methods

This retrospective study included 107 PA patients, and 186 pheochromocytoma patients as a control group, all of whom underwent adrenalectomy between January 2006 and November 2017 at Yonsei University Severance Hospital. The primary outcome was AKI within 48 hours after adrenalectomy. Univariate and multivariate logistic regression analyses were performed to identify predictors of AKI after adrenalectomy.

Results

Overall incidence of AKI was 49/293 (16.7%). In PA patients, the incidence of AKI was 29/107 (27.1%). In contrast, incidence of AKI was 20/186 (10.7%) in pheochromocytoma patients. Univariate and multivariate logistic regression analysis both showed a higher risk of postoperative AKI in PA patients compared to pheochromocytoma patients. In addition, old age, diabetes, longer duration of hypertension, lower preoperative estimated glomerular filtration rate, high aldosterone-cortisol ratio (ACR) and lateralization index (LI) were identified as independent risk factors for postoperative AKI in PA patients after unilateral adrenalectomy.

Conclusion

Incidence and risk of postoperative AKI were significantly higher in PA patients after surgical treatment. High ACR on the tumor side and high LI were associated with higher risk of AKI in PA patients compared to pheochromocytoma patients.

Aldosterone renin ratio and chronic kidney disease

As a component of the metabolic syndrome, hypertension (HTN) is increasing throughout the world with variable percentages, but mostly among developing world. Aldosterone plays a role in the relationship between aldosterone and nephropathy. We aimed to evaluate the relationship between aldosterone renin ratio (ARR) and chronic kidney disease (CKD). Variables drawn from the computerized hospital information database were all patients who had an ARR above 35 (if aldosterone reading was above 300 pmol/L). A total of 1584 patients, of whom 777 were male and 807 were female, with a mean [standard deviation (SD)] of 43.3 (16.5) years were studied. The mean ARR was 210.1 (SD: 246.4) in males and 214.3 and 210.1 in females, P = 0.51. The mean estimated glomerular filtration rate (eGFR) was 50.2 (SD 12.6); in males, it was 49.99 (0.90) and in females, it was 50.48 (0.92), P = 0.70. The regression model revealed a negative relationship between ARR and GFR with a coefficient of -2.08, 95% confidence interval: -4.6, 0.21, P = 0.07. CKD population with HTN tends to have a very high level of ARR, and those with advanced CKD have higher ARR. However, high ARR could have low eGFR and kidney dysfunction on follow-up. In view of high prevalence of noncommunicable disease and high early CKD population, there is an important need to consider comprehensive management strategies that involve the blockage of high renin-angiotensin-aldosterone and the use of mineralocorticosteroid receptor blockers.

Incidental Congestive Heart Failure in Patients With Aldosterone-Producing Adenomas

Background Previous studies show that patients with primary aldosteronism are associated with higher risk of congestive heart failure (CHF). However, the effect of target treatment to the incidental CHF has not been elucidated. We aimed to investigate the risk of new-onset CHF in patients with aldosterone-producing adenomas (APAs) and explore the effect of adrenalectomy on new onset of CHF. Methods and Results From 1997 to 2009, 688 APA were identified and matched with essential hypertension controls. The risks of developing incidental CHF (hazard ratio, 0.49; 95% CI, 0.31-0.75; P=0.001) and mortality (hazard ratio, 0.29; 95% CI, 0.20-0.44; P<0.001) were significantly lower in the APA group after targeted treatment. A total of 605 patients with APAs who underwent adrenalectomy lowered the risks of CHF (subdistribution hazard ratio, 0.55; 95% CI, 0.34-0.90; P=0.017) and mortality (adjusted hazard ratio, 0.27; 95% CI, 0.16-0.44; P<0.001) compared with essential hypertension controls. Conclusions In conclusion, for patients with APAs, adrenalectomy can be associated with lower risk of incidental CHF and all-cause mortality in a long-term follow-up.

Plasma Aldosterone Levels Are Not Associated With Cardiovascular Events Among Patients With High-Risk Vascular Disease: Insights From the ACCELERATE Trial

Background

The failure of cholesteryl ester transfer protein inhibitor torcetrapib was associated with an off‐target increase in plasma aldosterone. We sought to evaluate the impact of evacetrapib on plasma aldosterone level and determine the association between plasma aldosterone level and major adverse cardiovascular events among patients with stable high‐risk vascular disease enrolled in the ACCELERATE (Assessment of Clinical Effects of Cholesteryl Ester Transfer Protein Inhibition With Evacetrapib in Patients at a High Risk for Vascular Outcomes) trial.

Methods and Results

We included all patients with a plasma aldosterone level (N=1624) and determined the impact of evacetrapib exposure compared with placebo on plasma aldosterone levels after 12 months of treatment. Using baseline and postexposure aldosterone levels, hazard ratios for major adverse cardiovascular events (cardiovascular death, nonfatal myocardial infarction, cerebrovascular accident, hospitalization for unstable angina, and revascularization) with increasing quartile of baseline and percentage change in plasma aldosterone level at follow‐up were calculated. The average age was 65.2 years, 75.7% were men, 93.7% were hypertensive, 73.3% were diabetic, and 57.6% had a prior myocardial infarction. Baseline plasma aldosterone level (85.2 [43, 150] versus 86.8 [43, 155] pmol/L; P=0.81) and follow‐up percentage change (13.6% [−29, 88] versus 17.9% [−24, 87]; P=0.23) were similar between those who received evacetrapib and placebo. During median follow‐up of 28 months, major adverse cardiovascular events occurred in 263 patients (16.2%). The hazard ratios for increasing quartile of baseline or percentage change in plasma aldosterone level at follow‐up were not significant for major adverse cardiovascular events. These findings remained consistent when adjusting for significant characteristics.

Conclusions

Exposure to evacetrapib did not result in significant change in plasma aldosterone levels compared with placebo. Among patients with stable high‐risk vascular disease, plasma aldosterone levels were not a predictor for future cardiovascular events.

Clinical Trial Registration

URL: http://www.ClinicalTrials.gov. Unique identifier: NCT01687998.

Retinoic acid receptor α as a novel contributor to adrenal cortex structure and function through interactions with Wnt and Vegfa signalling

Primary aldosteronism (PA) is the most frequent form of secondary arterial hypertension. Mutations in different genes increase aldosterone production in PA, but additional mechanisms may contribute to increased cell proliferation and aldosterone producing adenoma (APA) development. We performed transcriptome analysis in APA and identified retinoic acid receptor alpha (RARα) signaling as a central molecular network involved in nodule formation. To understand how RARα modulates adrenal structure and function, we explored the adrenal phenotype of male and female Rarα knockout mice. Inactivation of Rarα in mice led to significant structural disorganization of the adrenal cortex in both sexes, with increased adrenal cortex size in female mice and increased cell proliferation in males. Abnormalities of vessel architecture and extracellular matrix were due to decreased Vegfa expression and modifications in extracellular matrix components. On the molecular level, Rarα inactivation leads to inhibition of non-canonical Wnt signaling, without affecting the canonical Wnt pathway nor PKA signaling. Our study suggests that Rarα contributes to the maintenance of normal adrenal cortex structure and cell proliferation, by modulating Wnt signaling. Dysregulation of this interaction may contribute to abnormal cell proliferation, creating a propitious environment for the emergence of specific driver mutations in PA.

Case detection in primary aldosteronism: high-diagnostic value of the aldosterone-to-renin ratio when performed under standardized conditions

OBJECTIVE

The aldosterone-to-renin ratio is widely used and is the recommended screening modality for primary aldosteronism by the Endocrine Society Guideline. However, studies on its diagnostic accuracy have been inconsistent, which is mainly because of methodological limitations. We set out to evaluate this diagnostic value by using a highly standardized study protocol, which is in line with the Endocrine Society Guideline recommendations regarding indications for screening, testing conditions and reference standards in daily clinical practice.

METHODS

In this prospective study, 233 consecutive patients referred to the University Medical Center Utrecht with difficult-to-control hypertension were enrolled. In addition to aldosterone-to-renin ratio measurements, all patients underwent a saline infusion test as a reference standard. A plasma aldosterone concentration greater than 280 pmol/l after saline infusion was considered diagnostic for aldosteronism and the plasma renin activity was assessed to exclude patients with secondary aldosteronism from the final primary aldosteronism diagnosis.

RESULTS

Correlation of the aldosterone-to-renin ratio (cut-off >5) with primary aldosteronism diagnosis showed 16 true positive, 29 false positive, 188 true negative and 0 false negative aldosterone-to-renin ratios, resulting in a sensitivity of 100% (CI 75.9-100), specificity of 86.7% (CI 81.2-90.7), positive-predictive value of 35.6% (CI 22.3-51.3) and negative-predictive value of 100% (CI 97.5-100.0). The corresponding area under the curve was 0.933 (CI 0.900-0.966).

CONCLUSION

These findings show that the aldosterone-to-renin ratio is a good screening modality for primary aldosteronism and is without a high risk of missing a primary aldosteronism diagnosis whenever performed under well standardized conditions.

Cortisol Excess in Patients With Primary Aldosteronism Impacts Left Ventricular Hypertrophy

CONTEXT

Primary aldosteronism (PA) represents the most frequent form of endocrine hypertension. Hyperaldosteronism and hypercortisolism both induce excessive left ventricular hypertrophy (LVH) compared with matched essential hypertensives. In recent studies frequent cosecretion of cortisol and aldosterone has been reported in patients with PA.

OBJECTIVE

Our aim was to investigate the impact of cortisol cosecretion on LVH in patients with PA. We determined 24-hour excretion of mineralocorticoids and glucocorticoids by gas chromatography-mass spectrometry and assessed cardiac remodeling using echocardiography initially and 1 year after initiation of treatment of PA.

PATIENTS

We included 73 patients from the Munich center of the German Conn's registry: 45 with unilateral aldosterone-producing adenoma and 28 with bilateral adrenal hyperplasia.

RESULTS

At the time of diagnosis, 85% of patients with PA showed LVH according to left ventricular mass index [(LVMI); median 62.4 g/m2.7]. LVMI correlated positively with total glucocorticoid excretion (r2 = 0.076, P = 0.018) as well as with tetrahydroaldosterone excretion (r2 = 0.070, P = 0.024). Adrenalectomy led to significantly reduced LVMI in aldosterone-producing adenoma (P < 0.001) whereas mineralocorticoid receptor antagonist therapy in bilateral adrenal patients with hyperplasia reduced LVMI to a lesser degree (P = 0.024). In multivariate analysis, the decrease in LVMI was positively correlated with total glucocorticoid excretion and systolic 24-hour blood pressure, but not with tetrahydroaldosterone excretion.

CONCLUSION

Cortisol excess appears to have an additional impact on cardiac remodeling in patients with PA. Treatment of PA by either adrenalectomy or mineralocorticoid receptor antagonist improves LVMI. This effect was most pronounced in patients with high total glucocorticoid excretion.

Risk of sepsis in patients with primary aldosteronism

BACKGROUND

The interaction between hyperaldosteronism and immune dysfunction has been reported and glucocorticoid co-secretion is frequently found in primary aldosteronism (PA). The aforementioned conditions raise the possibility of the infection risk; however, clinical episodes of sepsis have not been reported in PA.

METHODS

Using Taiwan's National Health Insurance Research Database between 1997 and 2009, we identified PA and aldosterone-producing adenoma (APA) matched with essential hypertension (EH) at a 1:1 ratio by propensity scores. The incidences of sepsis and mortality after the index date were evaluated, and the risk factors of outcomes were identified using adjusted Cox proportional hazards models and taking mortality as a competing risk.

RESULTS

We enrolled 2448 patients with PA (male, 46.08%; mean age, 48.4 years). There were 875 patients who could be ascertained as APA. Taking mortality as the competing risk, APA patients had a lower incidence of sepsis than their matched EH patients (hazard ratio (HR) 0.29; P < 0.001) after target treatments. Patients receiving adrenalectomy showed a benefit of decreasing the risk of sepsis (PA vs EH, HR 0.14, P = 0.001; APA vs EH, HR 0.16, P = 0.003), but mineralocorticoid receptor antagonist treatment may differ. Compared with matched control cohorts, patients with APA had a lower risk of all-cause mortality (PA, adjusted HR 0.84, P = 0.050; APA, adjusted HR 0.31, P < 0.001) after target treatments.

CONCLUSIONS

Our study demonstrated that patients with PA/APA who underwent adrenalectomy could attenuate the risk of sepsis compared with their matched EH patients. We further found that APA patients with target treatments could decrease all-cause mortality compared with EH patients.

High efficiency of the aldosterone-to-renin ratio in precisely detecting primary aldosteronism

The aldosterone-to-renin ratio (ARR) is extensively used for primary aldosteronism detection. Chemiluminescence immune assay (CLIA) is newly applied in aldosterone and renin detection for calculating the aldosterone-to-renin ratio. The performance of new ARR in aldosteronism detection is poorly evaluated. We aim to estimate the diagnostic value of this new aldosterone-to-renin ratio by highly standardized and clinically based protocol. Four hundred and forty-two patients were enrolled in our retrospective study. They went to the first affiliated hospital of Sun Yat-sen University with difficult-to-control hypertension. Primary aldosteronism diagnosis was based on clinical criteria, including a saline infusion test and other necessary inspections. ARR was calculated from plasma aldosterone and renin measured by CLIA. The cutoff value was determined and the diagnostic value was evaluated. The cutoff value of ARR for primary aldosteronism diagnosis was 28.3, with a sensitivity of 87.6%, specificity of 100%, negative-predictive value of 96.4%, and positive-predictive value of 100%. Then, we found that Age was weakly correlated with ARR. The cutoff values of ARR for primary aldosteronism diagnosis in 26-45-, 46-65-, and 66-85-year-old patients were, respectively, 29.45, 27.95, and 28.4, with sensitivities of 87.5%, 87.7%, and 87.5%, specificities of 100% for all, negative-predictive values of 97.7%, 94.3%, and 96.3%, and positive-predictive values of 100% for all. ARR generated by CLIA is a good diagnostic test for primary aldosteronism without making a false-positive diagnosis. Although ARR is correlated with age, ARR cutoff values for different ages are not more efficient than that for total sample in primary aldosteronism diagnosis.

Systolic heart failure in a patient with primary aldosteronism

A 53-year-old African man with a 25-year history of uncontrolled hypertension and systolic heart failure presented with an acute congestive heart failure exacerbation. He was found to have severe hypokalaemia, so additional testing was performed, and primary aldosteronism was confirmed. CT scan showed a 1.2×2.4 cm well-defined, homogeneous adenoma of the left adrenal gland. Adrenal vein sampling confirmed unilateral primary aldosteronism with lateralisation to the left adrenal gland. The patient was started on spironolactone and was referred to surgery for laparoscopic left adrenalectomy. Primary aldosteronism is associated with high cardiovascular morbidity and mortality due to activation of cardiac mineralocorticoid receptors. Studies suggest these negative effects can be reduced with early intervention and treatment. This case highlights the importance of investigating secondary causes of hypertension in young patients and the potential adverse cardiac effects of primary aldosteronism when it goes undiagnosed and untreated for years.

Primary aldosteronism: key characteristics at diagnosis: a trend toward milder forms

OBJECTIVE

Primary aldosteronism (PA) is the most common endocrine form of arterial hypertension. The German Conn's Registry's purpose is to improve treatment outcomes of PA. We assessed whether key clinical, biochemical and epidemiological characteristics of newly diagnosed PA cases have changed over time, potentially indicating a different screening and referral practice in Germany evolving from 2008 to 2016.

DESIGN

The German Conn's Registry is a multicenter database prospectively analyzing morbidity and long-term outcome of patients with PA.

METHODS

Phenotypic changes between three year periods were calculated using Mann-Whitney U tests and Kruskal-Wallis tests for independent variables.

RESULTS

Over three time periods from 2008 to 2016, we noted a relative decrease of unilateral PA cases (67 vs 43%). Significantly more females were diagnosed with PA (33 vs 43%). Median daily defined drug doses decreased (3.1 vs 2.0) in the presence of unchanged SBP (150 vs 150 mmHg), plasma aldosterone (199 vs 173 ng/L) and PRC (3.2 vs 3.2 U/L). Median ARR values decreased (70 vs 47 ng/U) and median potassium levels at diagnosis (3.5 vs 3.7 mmol/L) increased as the percentage of normokalemic patients (25 vs 41%), indicating milder forms of PA.

CONCLUSIONS

Our results are in accordance with an increased screening intensity for PA. We identified a trend toward diagnosing milder forms, increasingly more females and less unilateral cases of PA.

Fat-brain connections: Adipocyte glucocorticoid control of stress and metabolism

Glucocorticoids act via multiple mechanisms to mobilize energy for maintenance and restoration of homeostasis. In adipose tissue, glucocorticoids can promote lipolysis and facilitate adipocyte differentiation/growth, serving both energy-mobilizing and restorative processes during negative energy balance. Recent data suggest that adipose-dependent feedback may also be involved in regulation of stress responses. Adipocyte glucocorticoid receptor (GR) deletion causes increased HPA axis stress reactivity, due to a loss of negative feedback signals into the CNS. The fat-to-brain signal may be mediated by neuronal mechanisms, release of adipokines or increased lipolysis. The ability of adipose GRs to inhibit psychogenic as well as metabolic stress responses suggests that (1) feedback regulation of the HPA axis occurs across multiple bodily compartments, and (2) fat tissue integrates psychogenic stress signals. These studies support a link between stress biology and energy metabolism, a connection that has clear relevance for numerous disease states and their comorbidities.

Genetics of adrenocortical tumours

The recently available genomic sequencing techniques have led to breakthroughs in understanding of the underlying genetic mechanisms in adrenocortical tumours. Disease-causing mutations have been described for aldosterone-producing adenomas, cortisol-producing adenomas and adrenocortical carcinomas. Further, knowledge gained from transcriptome analyses and methylation arrays has provided new insights into the development of these tumours. Elucidation of the genomic landscape of adrenocortical tumours and improved techniques may in the future be useful for early diagnosis through the detection of mutated DNA in the circulation. Moreover, compounds that bind specifically to altered proteins may be used as screening targets or therapeutic agents. Regulation of cortisol release by interaction with an altered subunit in adenylate cyclase may be more complex, but may provide a new option for regulating steroid release. Information about derangements in adrenocortical carcinoma is already helpful for determining patient prognosis. With further knowledge, we may be able to identify novel biomarkers that effectively and noninvasively help in differentiating between benign and malignant disease. It is clear that the next few years will provide much novel information that hopefully will aid in the treatment of patients with adrenocortical tumours.

Cardiac Dysfunction in Association with Increased Inflammatory Markers in Primary Aldosteronism

BACKGROUND

Oxidative stress in primary aldosteronism (PA) is thought to worsen aldosterone-induced damage by activating proinflammatory processes. Therefore, we investigated whether inflammatory markers associated with oxidative stress is increased with negative impacts on heart function as evaluated by echocardiography in patients with PA.

METHODS

Thirty-two subjects (mean age, 50.3±11.0 years; 14 males, 18 females) whose aldosterone-renin ratio was more than 30 among patients who visited Severance Hospital since 2010 were enrolled. Interleukin-1β (IL-1β), IL-6, IL-8, monocyte chemoattractant protein 1, tumor necrosis factor α (TNF-α), and matrix metalloproteinase 2 (MMP-2), and MMP-9 were measured. All patients underwent adrenal venous sampling with complete access to both adrenal veins.

RESULTS

Only MMP-2 level was significantly higher in the aldosterone-producing adenoma (APA) group than in the bilateral adrenal hyperplasia (BAH). Patients with APA had significantly higher left ventricular (LV) mass and A velocity, compared to those with BAH. IL-1β was positively correlated with left atrial volume index. Both TNF-α and MMP-2 also had positive linear correlation with A velocity. Furthermore, MMP-9 showed a positive correlation with LV mass, whereas it was negatively correlated with LV end-systolic diameter.

CONCLUSION

These results suggest the possibility that some of inflammatory markers related to oxidative stress may be involved in developing diastolic dysfunction accompanied by LV hypertrophy in PA. Further investigations are needed to clarify the role of oxidative stress in the course of cardiac remodeling.

Risk factors for renal impairment revealed after unilateral adrenalectomy in patients with primary aldosteronism

Primary aldosteronism (PA) may induce significant decline of renal function and structural damage of kidney. However, it is difficult to evaluate accurate renal function in patients with PA, because glomerular hyperfiltration and aldosterone escape can conceal renal impairment. In this retrospective cohort study, we compared changes in renal function after unilateral adrenalectomy between patients with PA and patients with other adrenal diseases. Risk factors associated with postoperative renal impairment in patients with PA were analyzed.A total of 558 patients who received unilateral adrenalectomy between January 2002 and June 2013 were included: 136 patients with PA and 422 patients with other adrenal diseases (control). Postoperative serial changes in estimated glomerular filtration rate (eGFR) were analyzed in both groups. Multivariate analyses were performed to identify risk factors of renal impairment after adrenalectomy in all patients and the PA group. Postoperative renal impairment was defined as postoperative eGFR decline of >25% from preoperative eGFR. Chronic kidney disease (CKD) was defined as an eGFR <60 mL/min/1.73 m.There were no differences in preoperative eGFR between groups. The PA group showed a significant decrease in eGFR 3 days, 2 weeks, and 6 months after surgery compared to the control group. The PA group showed significant improvement of hypertension after surgery. In the PA group, 53 (39.0%) patients showed postoperative renal impairment. Multivariate regression analysis identified long-standing hypertension, low body mass index, low serum potassium, and high preoperative eGFR as risk factors for postoperative renal impairment. Among the 89 patients with preoperative eGFR ≥60 mL/min/1.73 m, 29 (32.6%) patients developed CKD postoperatively. Age, low serum potassium, low preoperative eGFR, and high serum cholesterol or uric acid were associated with the postoperative CKD development.Our study demonstrates that patients with PA with old age, low serum potassium, long-standing hypertension, and high serum uric acid or cholesterol are at risk of renal impairment after surgical treatment. High preoperative eGFR was also a risk factor for postoperative renal impairment, whereas low preoperative eGFR was a risk factor for postoperative CKD. Close monitoring of renal function and adequate management are required for patients with these risk factors.

Relationship of ocular microcirculation, measured by laser speckle flowgraphy, and silent brain infarction in primary aldosteronism

PURPOSE

Recent studies have shown that the risk of cerebro- and cardiovascular events (CVEs) is higher in patients with primary aldosteronism (PA) than in those with essential hypertension (EH), and that silent brain infarction (SBI) is a risk factor and predictor of CVEs. Here, we evaluated the relationship between findings from laser speckle flowgraphy (LSFG), a recently introduced non-invasive means of measuring mean blur rate (MBR), an important biomarker of ocular blood flow, and the occurrence of SBI in patients with PA.

METHODS

87 PA patients without symptomatic cerebral events (mean 55.1 ± 11.2 years old, 48 male and 39 female) were enrolled in this study. We measured MBR in the optic nerve head (ONH) with LSFG and checked the occurrence of SBI with magnetic resonance imaging. We examined three MBR waveform variables: skew, blowout score (BOS) and blowout time (BOT). We also recorded clinical findings, including age, blood pressure, and plasma aldosterone concentration.

RESULTS

PA patients with SBI (15 of 87 patients; 17%) were significantly older and had significantly lower BOT in the capillary area of the ONH than the patients without SBI (P = 0.02 and P = 0.03, respectively). Multiple logistic regression analysis revealed that age and BOT were independent factors for the presence of SBI in PA patients (OR, 1.15, 95% CI 1.01-1.38; P = .03 and OR, 0.73, 95% CI 0.45-0.99; P = .04, respectively).

CONCLUSION

PA patients with SBI were older and had lower MBR BOT than those without SBI. Our analysis showed that age was a risk factor for SBI, and that BOT was a protective factor, in patients with PA. This suggests that BOT, a non-invasive and objective biomarker, may be a useful predictor of SBI and form part of future PA evaluations and clinical decision-making.

Circulating aldosterone and natriuretic peptides in the general community: relationship to cardiorenal and metabolic disease

We sought to investigate the role of aldosterone as a mediator of disease and its relationship with the counter-regulatory natriuretic peptide (NP) system. We measured plasma aldosterone (n=1674; aged≥45 years old) in a random sample of the general population from Olmsted County, MN. In a multivariate logistic regression model, aldosterone analyzed as a continuous variable was associated with hypertension (odds ratio [OR]=1.75; 95% confidence interval [CI]=1.57-1.96; P<0.0001), obesity (OR=1.34; 95% CI=1.21-1.48; P<0.0001), chronic kidney disease (OR=1.39; 95% CI=1.22-1.60; P<0.0001), central obesity (OR=1.47; 95% CI=1.32-1.63; P<0.0001), metabolic syndrome (OR=1.41; 95% CI=1.26-1.58; P<0.0001), high triglycerides (OR=1.23; 95% CI=1.11-1.36; P<0.0001), concentric left ventricular hypertrophy (OR=1.22; 95% CI=1.09-1.38; P=0.0007), and atrial fibrillation (OR=1.24; 95% CI=1.01-1.53; P=0.04), after adjusting for age and sex. The associations with hypertension, central obesity, metabolic syndrome, triglycerides, and concentric left ventricular hypertrophy remained significant after further adjustment for body mass index, NPs, and renal function. Furthermore, aldosterone in the highest tertile correlated with lower NP levels and increased mortality. Importantly, most of these associations remained significant even after excluding subjects with aldosterone levels above the normal range. In conclusion, we report that aldosterone is associated with hypertension, chronic kidney disease, obesity, metabolic syndrome, concentric left ventricular hypertrophy, and lower NPs in the general community. Our data suggest that aldosterone, even within the normal range, may be a biomarker of cardiorenal and metabolic disease. Further studies are warranted to evaluate a therapeutic and preventive strategy to delay the onset and progression of disease, using mineralocorticoid antagonists or chronic NP administration in high-risk subjects identified by plasma aldosterone.

Beneficial effects of proanthocyanidins in the cardiac alterations induced by aldosterone in rat heart through mineralocorticoid receptor blockade

Aldosterone administration in rats results in several cardiac alterations. Previous studies have demonstrated that proanthocyanidins, phenolic bioactive compounds, have cardioprotective effects. We studied the potential beneficial effects of the proanthocyanidin-rich almond skin extract (PASE) on the cardiac alterations induced by aldosterone-salt treatment, their effects in mineralocorticoid receptor activity and we sought to confirm proanthocyanidins as the specific component of the extract involved in the beneficial cardiac effects. Male Wistar rats received aldosterone (1 mg/Kg/day) +1% NaCl for 3 weeks. Half of the animals in each group were simultaneously treated with either PASE (100 mg/Kg/day) or spironolactone (200 mg/Kg/day). The ability of PASE to act as an antagonist of the mineralocorticoid receptor was examined using a transactivation assay. High performance liquid chromatography was used to identify and to isolate proanthocyanidins. Hypertension and diastolic dysfunction induced by aldosterone were abolished by treatment with PASE. Expression of the aldosterone mediator SGK-1, together with fibrotic, inflammatory and oxidative mediators were increased by aldosterone-salt treatment; these were reduced by PASE. Aldosterone-salt induced transcriptional activity of the mineralocorticoid receptor was reduced by PASE. HPLC confirmed proanthocyanidins as the compound responsible for the beneficial effects of PASE. The effects of PASE were comparable to those seen with the mineralocorticoid antagonist, spironolactone. The observed responses in the aldosterone-salt treated rats together with the antagonism of transactivation at the mineralocorticoid receptor by PASE provides evidence that the beneficial effect of this proanthocyanidin-rich almond skin extract is via as a mineralocorticoid receptor antagonist with proanthocyanidins identified as the compounds responsible for the beneficial effects of PASE.

Long-term effects of adrenalectomy or spironolactone on blood pressure control and regression of left ventricle hypertrophy in patients with primary aldosteronism

INTRODUCTION

Primary aldosteronism (PA) represents the most common cause of secondary hypertension. Beyond increased blood pressure, additional harmful effects of aldosterone excess including inappropriate left ventricle (LV) hypertrophy were found. We evaluated the effect of adrenalectomy and spironolactone on blood pressure and myocardial remodelling in a long-term follow-up study.

METHODS

Thirty-one patients with PA were recruited. Fifteen patients with confirmed aldosterone-producing adenoma underwent adrenalectomy; in the remaining 16 patients, treatment with spironolactone was initiated. Laboratory data, 24-hour ambulatory blood pressure monitoring (ABPM) and echocardiography parameters were evaluated at baseline and at a median follow-up of 64 months.

RESULTS

Both approaches reduced blood pressure (p = 0.001 vs. baseline). In both groups we observed a decrease in end-diastolic (p = 0.04, p = 0.01) and end-systolic LV cavity diameters (p = 0.03, p = 0.01). Interventricular septum and posterior wall thickness reduction was significant only after adrenalectomy (p = 0.01, p = 0.03) as was reduction of LV mass index (p = 0.004). A trend to lower LV mass on spironolactone was caused predominantly by diminution of the LV cavity, which was reflected in increased relative wall thickness (p = 0.05).

CONCLUSIONS

Although both surgical and conservative treatment can induce a long-term decrease of blood pressure, adrenalectomy seems to be more effective in reduction of LV mass, as it reverses both wall thickening and enlargement of the LV cavity.

Risk of ischemic stroke in primary aldosteronism patients

BACKGROUND

High aldosterone concentrations are associated with the risk of stroke that is independent of blood pressure levels. We investigated the risk of ischemic stroke in primary aldosteronism (PA) patients.

METHODS

This retrospective case-control study was based on the Taiwan Primary Aldosteronism Investigation (TAIPAI) database from 2004 to 2010. The study group comprised the patients who developed ischemic stroke after the diagnosis of PA. The PA patients who did not develop stroke were matched according to age and sex as the control group. A multivariate logistic regression model was performed to determine the risk factors of ischemic stroke.

RESULTS

Of 339 patients diagnosed with PA, 22 patients (6.5%) developed de novo ischemic stroke. The PA patients with stroke suffered from a longer hypertensive period (11.0±6.5 vs 7.8±8.3, P=.007) and a higher prevalence of proteinuria than those who did not develop stroke (40.9% vs 12.9%, P=.002). A multivariate logistic regression model showed that PA patients with proteinuria (HR 3.58, P=.02), preexisting coronary artery disease (HR 11.12, P<.001) or left ventricular hypertrophy (HR 3.09, P=.047) were associated with an increased risk of ischemic stroke.

CONCLUSIONS

Proteinuria, a medical history of coronary artery disease or left ventricular hypertrophy, was associated with an increased risk of ischemic stroke in PA patients. Our results suggest that a public health initiative is necessary to enhance the follow-up of proteinuria and to manage subsequent stroke among patients with aldosteronism.

Aldosterone dysregulation with aging predicts renal vascular function and cardiovascular risk

Aging and abnormal aldosterone regulation are both associated with vascular disease. We hypothesized that aldosterone dysregulation influences the age-related risk of renal vascular and cardiovascular disease. We conducted an analysis of 562 subjects who underwent detailed investigations under conditions of liberal and restricted dietary sodium intake (1124 visits) in the General Clinical Research Center. Aldosterone regulation was characterized by the ratio of maximal suppression to stimulation (supine serum aldosterone on a liberal sodium diet divided by the same measure on a restricted sodium diet). We previously demonstrated that higher levels of this Sodium-modulated Aldosterone Suppression-Stimulation Index (SASSI) indicate greater aldosterone dysregulation. Renal plasma flow (RPF) was determined via p-aminohippurate clearance to assess basal renal hemodynamics and the renal vascular responses to dietary sodium manipulation and angiotensin II infusion. Cardiovascular risk was calculated using the Framingham Risk Score. In univariate linear regression, older age (β=-4.60; P<0.0001) and higher SASSI (β=-58.63; P=0.001) predicted lower RPF and a blunted RPF response to sodium loading and angiotensin II infusion. We observed a continuous, independent, multivariate-adjusted interaction between age and SASSI, where the inverse relationship between SASSI and RPF was most apparent with older age (P<0.05). Higher SASSI and lower RPF independently predicted higher Framingham Risk Score (P<0.0001) and together displayed an additive effect. Aldosterone regulation and age may interact to mediate renal vascular disease. Our findings suggest that the combination of aldosterone dysregulation and renal vascular dysfunction could additively increase the risk of future cardiovascular outcomes; therefore, aldosterone dysregulation may represent a modifiable mechanism of age-related vascular disease.

New insights into insulin action and resistance in the vasculature

Two-thirds of adults in the United States are overweight or obese, and another 26 million have type 2 diabetes. Decreased insulin sensitivity in cardiovascular tissue is an underlying abnormality in these individuals. Insulin metabolic signaling increases endothelial cell nitric oxide (NO) production. Impaired vascular insulin sensitivity is an early defect leading to impaired vascular relaxation. In overweight and obese persons, as well as in those with hypertension, systemic and vascular insulin resistance often occur in conjunction with activation of the cardiovascular tissue renin-angiotensin-aldosterone system (RAAS). Activated angiotensin II type 1 receptor and mineralocorticoid receptor signaling promote the development of vascular insulin resistance and impaired endothelial NO-mediated relaxation. Research in this area has implicated excessive serine phosphorylation and proteasomal degradation of the docking protein insulin receptor substrate and enhanced signaling through hybrid insulin/insulin-like growth factor receptor as important mechanisms underlying RAAS impediment of downstream vascular insulin metabolic signaling. This review will present recent evidence supporting the notion that RAAS signaling represents a potential pathway for the development of vascular insulin resistance and impaired endothelial-mediated vasodilation.

Mutations in KCNJ5 determines presentation and likelihood of cure in primary hyperaldosteronism

INTRODUCTION

Primary hyperaldosteronism (PA) is a common cause of secondary hypertension. Two recurrent mutations (G151R and L168R) in the potassium channel gene KCNJ5 have been identified that affect the Kir3.4 potassium channel found in the cells of the zona glomerulosa of the adrenal gland. The aim of this study was to determine the prevalence of KCNJ5 mutations in an Australian cohort of patients and to correlate these findings with clinical outcome data, in order to describe the clinical impact on patients who harbour this mutation.

METHODS

Direct Sanger sequencing for KCNJ5 on DNA from adrenal tumour tissue of 83 patients with PA in a cohort study was undertaken and mutation status correlated with clinical outcome data.

RESULTS

Seventy-one of 83 patients (86%) had adrenocortical adenomas and 12 patients (14%) had bilateral adrenal hyperplasia. A total of 34 (41%) patients were found to have heterozygous somatic mutations in KCNJ5, G151R and L168R. No germ line mutations were identified. Patients with mutations were predominately female (68% versus 49%) and significantly younger at presentation (48 versus 55 years). When correlated with clinical data, our results demonstrated that patients with KCNJ5 mutations were more likely to be cured following surgery without the requirement for ongoing medications.

CONCLUSIONS

Our findings in a large Australian cohort show that patients with mutations in KCNJ5 present earlier with the signs and symptoms of PA benefit from surgical intervention. Moreover, our results highlight the importance of a thorough workup and management plan for younger patients who present with hypertension.

Cardiovascular complications associated with primary aldosteronism: a controlled cross-sectional study

A higher risk of cardiovascular events has been reported in patients with primary aldosteronism (PA) than in otherwise similar patients with essential hypertension (EH). However, the evidence is limited by small sample size and potential confounding factors. We, therefore, compared the prevalence of cardiovascular events in 459 patients with PA diagnosed in our hypertension unit from 2001 to 2006 and 1290 controls with EH. PA cases and EH controls were individually matched for sex, age (± 2 years), and office systolic blood pressure (± 10 mm Hg). Patients with PA and EH differed significantly in duration of hypertension, serum potassium, plasma aldosterone and plasma renin concentrations, aldosterone-to-renin ratio, and urinary aldosterone concentration (P<0.001 for all comparisons). The prevalence of electrocardiographic and echocardiographic left ventricular hypertrophy was about twice higher in patients with PA even after adjustment for hypertension duration. PA patients also had a significantly higher prevalence of coronary artery disease (adjusted odds ratio, 1.9), nonfatal myocardial infarction (adjusted odds ratio, 2.6), heart failure (adjusted odds ratio, 2.9), and atrial fibrillation (adjusted odds ratio, 5.0). The risks associated with PA were similar across levels of serum potassium and plasma aldosterone. To conclude, patients with PA are more likely to have had a cardiovascular complication at diagnosis than otherwise similar patients with EH. Target organ damage and complications disproportionate to blood pressure should be considered as an additional argument for suspecting PA in a given individual and possibly for broadening the scope of screening at the population level.

Impact of electrocardiographic findings for diagnosis of left ventricular hypertrophy in patients with primary aldosteronism

BACKGROUND

Compared to patients with similar levels of hypertension, patients with primary aldosteronism have a greater left ventricular hypertrophy (LVH). The presence of LVH should be detected as early as possible to prevent cardiovascular complications associated with the condition. We evaluated comparative diagnostic value of electrocardiographic (ECG) indexes for LVH in patients with primary aldosteronism.

METHODS

ECG and echocardiographic data were obtained in 88 patients with primary aldosteronism. We analyzed the four most commonly used ECG indexes, including Sokolow-Lyon index, Cornell voltage index, Cornell product index, and Gubner index.

RESULTS

Echocardiographic LVH was found in 35 patients (40%). Sensitivity ranged from 0% for Gubner index to 49% for Cornell product index. Specificity ranged from 81% for Sokolow-Lyon index to 100% for Gubner index. Sokolow-Lyon index (r=0.43, p<0.001), Cornell voltage index (r=0.55, p<0.001) and Cornell product index (r=0.52, p<0.001) correlated significantly with left ventricular mass (LVM) index. No significant correlation was found between Gubner index and LVM index.

CONCLUSIONS

ECG indexes had a reasonably high specificity, but a low sensitivity for LVH in patients with primary aldosteronism. Cornell voltage index and Cornell product index had a better diagnostic value of LVH, and had a better correlation with LVM index in these patients.

Structural determinants of ligand binding to the mineralocorticoid receptor

The first and critical step in the mechanism of aldosterone action is its binding to the mineralocorticoid receptor (MR), a member of the nuclear receptor superfamily. Over the last 40 years, numerous studies have attempted to determine the structural determinants of ligand-binding to MR. An initial set of data showed that hsp90 is bound to the receptor via specific regions and maintains it in a ligand-binding competent state. Site-directed mutagenesis and functional studies guided by a 3D model of the MR ligand-binding domain (LBD) made it possible to identify the residues responsible for the high affinity and selectivity for aldosterone, and to characterize the mechanisms of MR activation and inactivation. The recent determination of the X-ray crystal structures of the LBD of the wild-type MR and MR(S810L), which is responsible for a familial form of hypertension, has made it possible to elucidate the peculiar mechanism of activation of MR(S810L) and established a clear structure/activity relationship for steroidal and non-steroidal MR antagonists.

Kidney in primary aldosteronism: A key determinant of treatment outcome

Recently, it has been suggested that primary aldosteronism (PA) is associated with a variety of cardiac, vascular, metabolic, and renal sequelae that reflect the capability of elevated aldosterone to induce organ damage beyond that induced by hypertension itself. The evidence supporting of these views has been obtained from experiments conducted in rodents and clinical studies conducted in patients with this endocrine disorder. It has been suggested that untoward effects of high-salt intake are dependent on activation of mineralocorticoid receptors that might result from increased oxidative stress and changes in the intracellular redox potential. Unilateral adrenalectomy or treatment with mineralocorticoid receptor antagonists are the current options for treating an aldosterone-producing adrenal adenoma or idiopathic adrenal hyperplasia. Treatments are largely effective in correcting hypertension and hypokalemia, and currently available information on their capability to prevent deterioration of renal function indicates that surgery and medical treatment are equally beneficial in the long term. This editorial review will focus on the renal aspects of PA and highlights the role of the kidney as a key determinant of both adaptation to aldosterone-induced volume retention and response of blood pressure to treatment.