Cardiovascular complications in patients with primary aldosteronism

Extra cut-off value of aldosterone-to-renin ratio for screening primary aldosteronism in hypertensive patients with diabetes mellitus

Primary aldosteronism (PA) and diabetes mellitus (DM) may coexist. We previously found that DM and impaired glucose tolerance (IGT) may decrease the efficiency of the aldosterone-to-renin ratio (ARR) for screening PA. Thus, we wanted to determine appropriate ARR cut-off values for screening PA in patients with hypertension with DM and IGT. Data from 736 patients with hypertension were collected. They were divided into PA (77 cases), PA with DM (27 cases), PA with IGT (44 cases), hypertension without PA (353 cases), hypertension with DM (without PA, 127 cases), and hypertension with IGT (without PA, 108 cases). Receiver operating characteristic (ROC) curves were used to identify the appropriate ARR cut-off values in different conditions. Screening efficiencies of these cut-off values were evaluated across different groups. ARR cut-off values for screening PA in hypertensive patients without DM and IGT, with DM, and with IGT were 29.65, 23.15, and 26.9, respectively. All cut-off values demonstrated high sensitivity and specificity: 92.2% and 88.7%, 92.6% and 79.5%, and 88.6% and 85.2%, respectively, and areas under the ROC curves were 0.941, 0.904, and 0.909, respectively. Our results suggest that extra ARR cut-off values may be necessary for effective screening PA in hypertensive patients with DM and IGT, particularly in those with DM.

Transient Ischaemic Attack in a Patient With Conn Syndrome: A Case Report and Literature Review on the Importance of Identifying Secondary Hypertension

BACKGROUND/AIM

Transient ischaemic attack (TIA) is characterised by a temporary neurological dysfunction resulting from focal ischaemia in the brain, spinal cord or retina without acute infarction. These episodes typically last less than 24 hours and are significant predictors of subsequent ischaemic strokes. Hypertension is a major risk factor for cerebrovascular events, and primary aldosteronism (PA) is recognised as a common cause of secondary hypertension. This case report presents a male patient with secondary hypertension due to Conn Syndrome, a form of PA, who experienced a TIA manifesting as left leg weakness, underscoring the heightened stroke risk associated with secondary hypertension.

CASE REPORT

A 78-year-old male with secondary hypertension caused by Conn Syndrome presented with an episode of left leg weakness that resolved within 24 hours. After ruling out other potential causes such as metabolic disturbances, infections, and structural brain lesions, he was diagnosed with TIA and treated with dual antiplatelet therapy. A carotid ultrasound revealed significant stenosis, leading to a referral for carotid endarterectomy. Long-term management included clopidogrel monotherapy and optimising hypertension control.

CONCLUSION

This case highlights the increased stroke risk in patients with Conn Syndrome-related hypertension, emphasising the importance of early recognition and optimising hypertension management in patients with secondary hypertension to prevent future cerebrovascular events.

Management of adreno-cortical adenomas using microwave ablation: study of the effects of the fat tissue

BACKGROUND AND OBJECTIVES

Adrenocortical neoplasms are the main causes of secondary hypertension and related comorbidities including hypokalemia and cardiovascular diseases. Conventional techniques for the management of this condition are often invasive and not resolutive. Recent studies proposed microwave thermal ablation (MWA) to eradicate adrenocortical adenomas arising in proximity to sensitive structures. This study explores a new MWA approach to selectively direct the electromagnetic energy into the target and shield the surrounding tissues. The new solution relies on the anatomical and dielectric characteristics of the adrenal gland and the surrounding fat capsule.

METHODS

A 3 D model of the adrenal gland is developed, and a cooled microwave applicator is placed parallel to the interface between the fat and adrenal tissue. Numerical simulations are conducted at 2.45 GHz accounting for two energy delivery settings, two orientations of the applicator and blood perfusion of the tissues. Ex vivo and in vivo ablation procedures are conducted on ovine adrenal glands. Histology analysis completes the experimental studies.

RESULTS

Numerical results show asymmetric ablation profiles in ex vivo and in vivo conditions. The asymmetry ratio is influenced by the procedure settings and orientation of the applicator. Ablation zones obtained experimentally agree with those predicted by the numerical simulations. Histology analysis confirms irreversible cellular changes only in the adrenal tissue close to the applicator.

CONCLUSIONS

The outcomes show that the dielectric contrast between the fat layer and tissue target can be a tool in MWA to shape ablation zones to protect the surrounding structures from excessive temperature increases.

Primary Aldosteronism and Ischemic Heart Disease

Cardiovascular disease, in particular ischemic heart disease is a major cause of morbidity and mortality worldwide. Primary aldosteronism is the leading cause of secondary hypertension, yet commonly under diagnosed, and represents a major preventable risk factor. In contrast to historical teaching, recent studies have shown that excess aldosterone production is associated with increased burden of ischemic heart disease disproportionate to the effects caused by hypertension alone. Aldosterone through its genomic and non-genomic actions exerts various detrimental cardiovascular changes contributing to this elevated risk. Recognition of primary hyperaldosteronism and understanding the distinctive pathophysiology of ischemic heart disease in primary aldosteronism is crucial to develop strategies to improve outcomes.

Image-based computer modeling assessment of microwave ablation for treatment of adrenal tumors

PURPOSE

To assess the feasibility of delivering microwave ablation for targeted treatment of aldosterone producing adenomas using image-based computational models.

METHODS

We curated an anonymized dataset of diagnostic ¹¹C-metomidate PET/CT images of 14 patients with aldosterone producing adenomas (APA). A semi-automated approach was developed to segment the APA, adrenal gland, and adjacent organs within 2 cm of the APA boundary. The segmented volumes were used to implement patient-specific 3D electromagnetic-bioheat transfer models of microwave ablation with a 2.45 GHz directional microwave ablation applicator. Ablation profiles were quantitatively assessed based on the extent of the APA target encompassed by an ablative thermal dose, while limiting thermal damage to the adjacent normal adrenal tissue and sensitive critical structures.

RESULTS

Across the 14 patients, adrenal tumor volumes ranged between 393 mm³ and 2,395 mm³. On average, 70% of the adrenal tumor volumes received an ablative thermal dose of 240CEM43, while limiting thermal damage to non-target structures, and thermally sparing 83.5-96.4% of normal adrenal gland. Average ablation duration was 293 s (range: 60-600 s). Simulations indicated coverage of the APA with an ablative dose was limited when the axis of the ablation applicator was not well aligned with the major axis of the targeted APA.

CONCLUSIONS

Image-based computational models demonstrate the potential for delivering microwave ablation to APA targets within the adrenal gland, while limiting thermal damage to surrounding non-target structures.

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.

Oral Salt Loading Test is Associated With 24-Hour Blood Pressure and Organ Damage in Primary Aldosteronism Patients

Objective

In the present study, we investigated the most useful confirmatory test for reflecting the severity of primary aldosteronism (PA), by evaluating 24-hour blood pressure (BP), urine albumin, left ventricular mass (LVM), and intima media thickness (IMT).

Methods

This study included 113 patients (80 PA and 33 non-PA hypertensive patients) who were admitted to Oita University Hospital and evaluated using ambulatory blood pressure monitoring (ABPM). First, casual blood pressure (BP) and ABPM parameters were compared between PA and non-PA patients. Second, patients were divided into PA-positive and PA-negative groups based on confirmatory tests, including the saline infusion test (SIT), captopril challenge test (CCT), and oral salt loading test (OSLT), and casual BP and ABPM parameters were compared between the 2 groups. In addition, urine albumin excretion, LVM, and maximum IMT as markers of organ damage were compared between the 2 groups.

Results

The ABPM parameters but not casual BP, were higher in PA patients than in non-PA patients. Nocturnal and 24-hour systolic BP (SBP) in OSLT-positive patients were significantly higher than in OSLT-negative patients. ABPM parameters in other confirmatory tests were not different between the PA-positive and PA-negative groups. Urine albumin excretion in OSLT-positive patients was significantly higher than in the OSLT-negative patients. However, in other confirmatory tests, organ damage markers were not different between the 2 groups.

Conclusion

The OSLT is potentially useful not only for the diagnosis of PA but also for assessment of 24-hour SBP and organ damage, as indicated by urine albumin excretion.

Performance of the unilateral AV/IVC index in primary hyperaldosteronism subtype prediction: A validation study in a single tertiary centre

BACKGROUND

Failure of cannulation of the right adrenal vein is frequent during AVS for investigation of primary aldosteronism (PA). The aldosterone:cortisol ratio of either adrenal vein compared with the inferior vena cava (AV/IVC index) has been proposed to differentiate between unilateral and bilateral disease, and aid in lateralization of unilateral disease.

METHODS

Sixty-two patients with unilateral or bilateral PA identified by either successful bilateral (45 patients) or unilateral (17 patients) adrenal vein cannulation, and with biochemical remission following surgery were enrolled into the analysis. The diagnostic performances of the previously identified AV/IVC index cut-offs of ≥5.5 to predict ipsilateral disease and ≤0.5 to predict contralateral disease were validated using data from the entire cohort.

RESULTS

Fifty-three patients had unilateral PA and 9 patients bilateral PA. The area under ROC curve (AUROC) of the AV/IVC cut-off ≤0.5 for identifying unilateral aldosterone secretion from the contralateral adrenal was 0.95 (95% CI; 0.88-0.99), whereas the AUROC of the AV/IVC cut-off ≥5.5 for identifying unilateral aldosterone secretion from ipsilateral adrenal was 0.96 (95% CI; 0.92-0.99). The AV/IVC index cut-off value of 0.5 had 93% sensitivity and 91% specificity, and the AV/IVC index cut-off value of 5.5 had 21% sensitivity and 100% specificity. The optimal AV/IVC cut-offs to achieve 100% specificity for our cohort were >2.4 and <0.1 to predict ipsilateral and contralateral disease.

CONCLUSION

Our data confirm that the AV/IVC index is a potential tool for subtype classification and lateralization in patients with PA in the setting of failed bilateral, but successful unilateral, adrenal vein cannulation during AVS.

Maintenance of long-term blood pressure control and vascular health by low-dose amiloride-based therapy in hyperaldosteronism

Whether aldosterone itself contributes directly to macro- or microcirculatory disease in man or to adverse cardiovascular outcomes is not fully known. We report our long-term single-practice experience in an unusual group of five patients with chronic hyperaldosteronism (HA, including three with glucocorticoid-remediable aldosteronism, GRA) treated with low-dose amiloride (a specific epithelial sodium channel [ENaC] blocker) 5-10 (mean 7) mg daily for 14-28 (mean 20) years. Except for one GRA diagnosed in infancy, all had severe resistant hypertension. In each case, BP was normalized within 1-4 weeks after starting amiloride and office BP's remained well controlled throughout the next two decades. 24-hour ambulatory BP monitoring with pulse wave analysis (cardiac output, vascular resistance, augmentation index, reflection magnitude), regional pulse wave velocities, pulse stiffening ratio, ankle-brachial index, serum creatinine, estimated glomerular filtration rate, and spot urinary albumin:creatinine ratio were measured after a mean of 18 years; all of these indicators were essentially normal. Over two additional years of observation (100 patient-years total), no cardiovascular or renal event occurred. We conclude that long-term ENaC blockade with amiloride can normalize BP and protect macro- and microvascular function in patients with HA. This suggests that either (a) putative vasculopathic effects of aldosterone are mediated via ENaC or (b) aldosterone may not play a direct role in age-dependent vasculopathic changes in humans independent of blood pressure. These findings, coupled with our literature review in both animal and human results, underscore the need for additional studies.

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.

Long-term BP control and vascular health in patients with hyperaldosteronism treated with low-dose, amiloride-based therapy

Whether aldosterone itself contributes directly to macro- or microcirculatory disease in man or to adverse cardiovascular outcomes is not fully known. We report our long-term single-practice experience in 5 patients with chronic hyperaldosteronism (HA, including 3 with glucocorticoid remediable aldosteronism, GRA) treated with low-dose amiloride (a specific epithelial sodium channel [ENaC] blocker) 5-10 (mean 7) mg daily for 14-28 (mean 20) years. Except for 1 GRA diagnosed in infancy, all had severe resistant hypertension. In each case, BP was normal or near-normal within 1-4 weeks after starting amiloride and office BP's were well controlled for 20 years thereafter. Vascular studies and 24-hour ambulatory BP monitoring with pulse wave analysis (cardiac output, vascular resistance, augmentation index, and reflection magnitude) were assessed after a mean of 18 years as were regional pulse wave velocities, pulse stiffening ratio, ankle-brachial index, serum creatinine, estimated glomerular filtration rate, and spot urinary albumin:creatinine ratio. All indicators were completely normal in all patients after 18 years of amiloride, and none had a cardiovascular event during the 20-year mean follow-up. We conclude that long-term ENaC blockade can normalize BP and protect macro- and microvascular function in patients with HA. This suggests that (a) any vasculopathic effects of aldosterone are mediated via ENaC, not MR activation itself, and are fully preventable or reversible with ENaC blockade or (b) aldosterone may not play a major BP-independent role in human macro- and microcirculatory diseases. These and other widely divergent results in the literature underscore the need for additional studies regarding aldosterone, ENaC, and vascular disease.

Elevated plasma aldosterone levels are associated with a reduction in retinal ganglion cell survival

Objective:

The purpose of this article is to investigate the relationship between the plasma concentration of aldosterone and changes in the number of retinal ganglion cells (RGCs) after systemic administration of aldosterone.

Methods:

An osmotic minipump that was subcutaneously implanted into the midscapular region of rats administered 40, 80 or 160 μg/kg/day aldosterone or vehicle. Enzyme immunoassay kits were used to measure the plasma aldosterone concentrations two weeks after the systemic administration of aldosterone or vehicle. Six weeks after these systemic administrations, the number of RGCs was measured.

Results:

The plasma aldosterone concentrations at two weeks after systemic administration of vehicle or 160 μg/kg/day aldosterone were 238 ± 17 pg/ml and 1750 ± 151 pg/ml (748.5% ± 183.2%), respectively. There was a significant decrease in the number of RGCs in the central retina of the rats after the administration of either 80 or 160 μg/kg/day aldosterone. In the peripheral retina, however, there was a significant decrease in the number of RGCs in 40, 80 or 160 μg/kg/day aldosterone. There was a significant correlation between the number of RGCs and plasma aldosterone concentration.

Conclusions:

After systemic administration of aldosterone, there was a negative correlation between the plasma aldosterone concentration and the number of RGCs.

Pathophysiological mechanisms of mineralocorticoid receptor-dependent cardiovascular and chronic kidney disease

Accumulating evidence has indicated the potential contributions of aldosterone and mineralocorticoid receptor (MR) to the pathophysiology of cardiovascular disease (CVD) and chronic kidney disease (CKD). Patients with primary aldosteronism have a higher risk of CVD and CKD than those with essential hypertension. MR is strongly expressed in endothelial cells, vascular smooth muscle cells, cardiomyocytes, fibroblasts, macrophages, glomerular mesangial cells, podocytes, and proximal tubular cells. In these cardiovascular and renal cells, aldosterone-induced cell injury is prevented by MR blockade. Interestingly, MR antagonists elicit beneficial effects on CVD and CKD in subjects with low or normal plasma aldosterone levels. Recent studies have shown that during development of CVD and CKD, cardiovascular and renal MR is activated by glucocorticoid and ligand-independent mechanisms, such as Rac1 signaling pathways. These data indicate that inappropriate activation of local MR contributes to cardiovascular and renal tissue injury through aldosterone-dependent and -independent mechanisms. In this review, recent findings on the specific role of cardiovascular and renal MR in the pathogenesis of CVD and CKD are summarized.

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.

Gene expression changes in the retina after systemic administration of aldosterone

PURPOSE

Retinal ganglion cell (RGC) loss associated with thinning of the retinal nerve fiber layer without elevated intraocular pressure (IOP) occurs after the systemic administration of aldosterone. Since it is important to determine the mechanism of cell death independent of the IOP, we examined gene expression changes in the retina after the systemic administration of aldosterone.

METHODS

Following subcutaneous implantation of an osmotic minipump into the mid-scapular region of rats, we administered an 80 μg/kg/day dose of aldosterone. Differences in the gene expression in the retina between normal rats and aldosterone-treated rats were investigated using microarrays. Real-time PCR was used to confirm the differential expression.

RESULTS

Analysis of the microarray data sets revealed the upregulation of 24 genes and the downregulation of 24 genes of key apoptosis-specific genes. Real-time PCR revealed 4 genes (Cdkn1a, Tbox5, Pf4, Vdr) were upregulated while 12 genes (Acvr1c, Asns, Bard1, Card9, Crh, Fcgr1a, Inhba, Kcnh8, Lck, Phlda1, Ptprc, Sh3rf1) were downregulated.

CONCLUSIONS

Significant increases and decreases were noted in several genes after the systemic administration of aldosterone. Further studies will need to be undertaken in order to definitively clarify the role of these genes in the eyes of animals with normal-tension glaucoma.

Complete remission of hypertension in a hemodialysis patient after adrenalectomy for primary aldosteronism and renal transplantation

A 64-year-old man was admitted to our hospital for the hormonal evaluation of a right adrenal adenoma. He had been diagnosed with severe proteinuria and hypertension, and antihypertensive treatment was started at the age of 60. His renal function gradually declined, and hemodialysis was begun at the age of 64. Since his blood pressure was uncontrollable and resistant to antihypertensive treatment, an endocrinological examination was performed for an incidental right adrenal mass detected by computed tomography. The results of screening, including captopril challenge and an adrenocorticotropin stimulation test for primary aldosteronism, and adrenal venous sampling suggested excessive aldosterone secretion from the right adrenal gland. Adrenalectomy was performed; his blood pressure decreased and became well-controlled with a reduced antihypertensive regimen. Furthermore, he received renal transplantation which resulted in normalization of his serum potassium level, improvement of renal function and hormonal levels such as plasma renin activity and aldosterone concentration, and satisfactory blood pressure without any antihypertensive medications. This case is extremely important to demonstrate the effects of adrenalectomy for primary aldosteronism in a hemodialysis patient. It is possible that adrenalectomy may be a useful treatment for primary aldosteronism even in patients undergoing hemodialysis. Careful long-term follow-up of our case and investigations of the efficacy of adrenalectomy in similar cases are needed to address this issue.

Managing resistant hypertension: focus on mineralocorticoid-receptor antagonists

Mineralocorticoid-receptor antagonists (MRAs) have proven to be effective in some types of hypertension, especially in resistant hypertension (RHTN). In this phenotype of hypertension, the renin-angiotensin-aldosterone pathway plays an important role, with MRAs being especially effective in reducing blood pressure. In this review, we show the relevance of aldosterone in RHTN, as well as some clinical characteristics of this condition and the main concepts involving its pathophysiology and cardiovascular damage. We analyzed the mechanisms of action and clinical effects of two current MRAs - spironolactone and eplerenone - both of which are useful in RHTN, with special attention to the former. RHTN represents a significant minority (10%-15%) of hypertension cases. However, primary-care physicians, cardiologists, nephrologists, neurologists, and geriatricians face this health problem on a daily basis. MRAs are likely one of the best pharmacological options in RHTN patients; however, they are still underused.

Effect of Treatment on Body Fluid in Patients with Unilateral Aldosterone Producing Adenoma: Adrenalectomy versus Spironolactone

Aldosterone affects fluid retention in the body by affecting how much salt and water that the kidney retains or excretes. There is limited information about the effect of prolonged aldosterone excess and treatment on body fluid in primary aldosteronism (PA) patients. In this study, body composition changes of 41 PA patients with unilateral aldosterone producing adenoma (APA) were assessed by a bio-impedance spectroscopy device. Patients with APA receiving adrenalectomy, as compared with those treated with spironolactone, had significantly lower relative overhydration (OH) and urine albumin excretion, and significantly higher urine sodium excretion four weeks after treatment. These differences dissipated 12 weeks after the initial treatment. Independent factors to predict decreased relative OH four weeks after treatment were male patients and patients who experienced adrenalectomy. Patients who underwent adrenaelctomy had significantly decreased TNF-α and increased serum potassium level when compared to patients treated with spironolactone 4 and 12 weeks after treatment. In this pilot study, we found that adrenalectomy leads to an earlier increase in renal sodium excretion and decreases in body fluid content, TNF-α, and urine albumin excretion. Adrenalectomy yields a therapeutic effect more rapidly, which has been shown to ameliorate overhydration in PA patients.

Progress in aldosteronism: a review of the prevalence of primary aldosteronism in pre-hypertension and hypertension

Primary aldosteronism (PA) secondary to excessive and/or autonomous aldosterone secretion from the renin-angiotensin system accounts for ∼10% of cases of hypertension and is primarily caused by bilateral adrenal hyperplasia (BAH) or aldosterone-producing adenomas (APAs). Although the diagnosis has traditionally been supported by low serum potassium levels, normokalaemic and even normotensive forms of PA have been identified expanding further the clinical phenotype. Moreover, recent evidence has shown that serum aldosterone correlates with increased blood pressure (BP) in the general population and even moderately raised aldosterone levels are linked to increased cardiovascular morbidity and mortality. In addition, aldosterone antagonists are effective in BP control even in patients without evidence of dysregulated aldosterone secretion. These findings indicate a higher prevalence of aldosterone excess among hypertensive patients than previously considered that could be attributed to disease heterogeneity, aldosterone level fluctuations related to an ACTH effect or inadequate sensitivity of current diagnostic means to identify apparent aldosterone excess. In addition, functioning aberrant receptors expressed in the adrenal tissue have been found in a subset of PA cases that could also be related to its pathogenesis. Recently a number of specific genetic alterations, mainly involving ion homeostasis across the membrane of zona glomerulosa, have been detected in ∼50% of patients with APAs. Although specific genotype/phenotype correlations have not been clearly identified, differential expression of these genetic alterations could also account for the wide clinical phenotype, variations in disease prevalence and performance of diagnostic tests. In the present review, we critically analyse the current means used to diagnose PA along with the role that ACTH, aberrant receptor expression and genetic alterations may exert, and provide evidence for an increased prevalence of aldosterone dysregulation in patients with essential hypertension and pre-hypertension.

Pathophysiology, diagnosis, and treatment of mineralocorticoid disorders

The renin-angiotensin-aldosterone system (RAAS) is a major regulator of blood pressure control, fluid, and electrolyte balance in humans. Chronic activation of mineralocorticoid production leads to dysregulation of the cardiovascular system and to hypertension. The key mineralocorticoid is aldosterone. Hyperaldosteronism causes sodium and fluid retention in the kidney. Combined with the actions of angiotensin II, chronic elevation in aldosterone leads to detrimental effects in the vasculature, heart, and brain. The adverse effects of excess aldosterone are heavily dependent on increased dietary salt intake as has been demonstrated in animal models and in humans. Hypertension develops due to complex genetic influences combined with environmental factors. In the last two decades, primary aldosteronism has been found to occur in 5% to 13% of subjects with hypertension. In addition, patients with hyperaldosteronism have more end organ manifestations such as left ventricular hypertrophy and have significant cardiovascular complications including higher rates of heart failure and atrial fibrillation compared to similarly matched patients with essential hypertension. The pathophysiology, diagnosis, and treatment of primary aldosteronism will be extensively reviewed. There are many pitfalls in the diagnosis and confirmation of the disorder that will be discussed. Other rare forms of hyper- and hypo-aldosteronism and unusual disorders of hypertension will also be reviewed in this article.

Primary aldosteronism presenting with an atypical aldosterone-renin ratio in the acute phase of cerebral hemorrhage

The aldosterone-renin ratio (ARR) is considered to be the most reliable and sensitive screening parameter for primary aldosteronism (PA). However, little is known regarding how stroke influences the ARR. We herein present a case of a 35-year-old man who was ultimately found to have PA after diagnostic challenges. The patient showed an atypical ARR in the acute phase of cerebral hemorrhage. We therefore conclude that the ARR may be inappropriately decreased immediately after stroke in patients with PA, presumably due to sympathetic activation and the effects of medications. When diagnosing PA in patients with stroke, we suggest reevaluating the ARR in the stable phase.

Treatment of Primary Aldosteronism and Organ Protection

Primary aldosteronism is a frequent form of secondary hypertension that had long been considered relatively benign. Experimental and clinical evidence collected in the last two decades, however, has clearly demonstrated that this endocrine disorder is associated with excess cardiovascular and renal complications as compared to essential hypertension. These complications reflect the ability of inappropriate elevation of plasma aldosterone to cause tissue damage beyond that induced by high blood pressure itself, thereby setting the stage for major cardiovascular and renal disease. Because of the impact of elevated aldosterone on organ damage, goals of treatment in patients with primary aldosteronism should not be limited to normalization of blood pressure, and prevention or correction of organ complications is mandatory. Treatment with mineralocorticoid receptor antagonists or unilateral adrenalectomy is the respective options for treatment of idiopathic adrenal hyperplasia or aldosterone-producing adenoma. Last years have witnessed a rapid growth in knowledge concerning the effects of these treatments on cardiovascular and renal protection. This paper is an overview of the cardiovascular and renal complications that occur in patients with primary aldosteronism and a summary of the results that have been obtained in the long term on cardiovascular and renal outcomes with either medical or surgical treatment.

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.

Primary aldosteronism in hypertensive patients: clinical implications and target therapy

BACKGROUND

The prevalence of primary aldosteronism (PA) in hypertensive patients varies according to diagnostic testing and ascertained normal cut-offs. The aim of this case-control study was to confirm the high prevalence of PA in a large hypertensive population and evaluate the antihypertensive effect of mineralocorticoid receptor antagonists (MRA) treatment.

MATERIAL AND METHODS

We investigated 327 hypertensive and 90 matched normotensive subjects with normal adrenal imaging. Serum aldosterone (ALD), active renin (REN) levels and aldosterone/active renin (ALD/REN) ratio were measured before and after a combined sodium chloride, fludrocortisone and dexamethasone suppression test (FDST). Post-FDST values were compared to cut-offs obtained from controls (post-FDST ALD 2·96 ng/dL and post-FDST ALD/REN 0·93 ng/dL/μU/mL). PA patients received MRA treatment.

RESULTS

By applying the combination of post-FDST ALD levels and ALD/REN ratio, 28·7% of the hypertensive patients had PA. There was a positive, albeit weak, correlation between systolic (SBP) and diastolic blood pressure (DBP) and ALD levels and/or ALD/REN ratio after the FDST (P < 0·0001). SBP was associated with a post-FDST ALD of 3·24 ng/dL and ALD/REN ratio of 0·90 ng/dL/μU/mL, whereas post-FDST ALD had an inverse association at serum K+ values of less than 3·9 mEq/L. MRA treatment in 69 PA patients, resulted in a significant reduction in the maximum SBP and DBP values (28 ± 15 and 14 ± 7 mmHg, respectively, P < 0·0001).

CONCLUSIONS

Using the FDST, an increased prevalence of PA in hypertensives was observed. Α significant blood pressure lowering effect was obtained with MRA treatment, implying that these agents may be beneficial in a significant number of hypertensive patients.

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.

Aldosterone and glomerular filtration--observations in the general population

Background

Increasing evidence suggests that aldosterone promotes renal damage. Since data on the association between aldosterone and renal function in the general population are sparse, we chose to address this issue. We investigated the associations between the plasma aldosterone concentration (PAC) or the aldosterone-to-renin ratio (ARR) and the estimated glomerular filtration rate (eGFR) in a sample of adult men and women from Northeast Germany.

Methods

A study population of 1921 adult men and women who participated in the first follow-up of the Study of Health in Pomerania was selected. None of the subjects used drugs that alter PAC or ARR. The eGFR was calculated according to the four-variable Modification of Diet in Renal Disease formula. Chronic kidney disease (CKD) was defined as an eGFR <60 ml/min/1.73 m².

Results

Linear regression models, adjusted for sex, age, waist circumference, diabetes mellitus, smoking status, systolic and diastolic blood pressures, serum triglyceride concentrations and time of blood sampling revealed inverse associations of PAC or ARR with eGFR (ß-coefficient for log-transformed PAC −3.12, p < 0.001; ß-coefficient for log-transformed ARR −3.36, p < 0.001). Logistic regression models revealed increased odds for CKD with increasing PAC (odds ratio for a one standard deviation increase in PAC: 1.35, 95% confidence interval: 1.06-1.71). There was no statistically significant association between ARR and CKD.

Conclusion

Our study demonstrates that PAC and ARR are inversely associated with the glomerular filtration rate in the general population.

Mineralocorticoid receptor blockade-a novel approach to fight hyperkalaemia in chronic kidney disease

Hyperkalaemia continues to be a major hazard of mineralocorticoid receptor blockade in an effort to retard the progression of chronic kidney disease (CKD). In cardiac patients on mineralocorticoid receptor blockade, RLY-5016 which captures K⁺ in the colon has been effective in reducing the risk of hyperkalaemia. This compound might be useful in CKD as well.

Aldosterone: a mediator of retinal ganglion cell death and the potential role in the pathogenesis in normal-tension glaucoma

Glaucoma is conventionally defined as a chronic optic neuropathy characterized by progressive loss of retinal ganglion cells (RGCs) and optic nerve fibers. Although glaucoma is often associated with elevated intraocular pressure (IOP), significant IOP reduction does not prevent progression of the disease in some glaucoma patients. Thus, exploring IOP-independent mechanisms of RGC loss is important. We describe chronic systemic administration of aldosterone and evaluate its effect on RGCs in rat. Aldosterone was administered via an osmotic minipump that was implanted subcutaneously into the mid-scapular region. Although systemic administration of aldosterone caused RGC loss associated with thinning of the retinal nerve fiber layer without elevated IOP, the other cell layers appeared to be unaffected. After chronic administration of aldosterone, RGC loss was observed at 2 weeks in the peripheral retina and at 4 weeks in the central retina. However, administration of mineralocorticoid receptor blocker prevented RGC loss. These results demonstrate aldosterone is a critical mediator of RGC loss that is independent of IOP. We believe this rat normal-tension glaucoma (NTG) animal model not only offers a powerful system for investigating the mechanism of neurodegeneration in NTG, but can also be used to develop therapies directed at IOP-independent mechanisms of RGC loss.

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.

Mineralocorticoid receptor antagonists and renal involvement in primary aldosteronism: opening of a new era

Primary aldosteronism (PA) is one of the commonest forms of curable hypertension, and use of the plasma aldosterone-to-renin ratio as a screening test has led to a more efficient identification of this condition. Both animal and human studies have indicated that PA is associated with a variety of cardiovascular and renal complications that reflect the capability of elevated aldosterone to induce tissue damage exceeding that induced by hypertension itself. Involvement of the kidney in PA is highly relevant because structural renal damage is associated with less favorable outcome, both in terms of blood pressure response to treatment and possibility to develop progressive renal failure. However, early involvement of the kidney in PA is characterized by functional changes that are largely reversible with treatment. Unilateral adrenalectomy or administration of mineralocorticoid receptor antagonists are the current options for treating an aldosterone-producing adenoma or idiopathic adrenal hyperplasia. Both treatments are effective in correcting hypertension and hypokalemia, and currently available information on their capability to prevent deterioration of renal function indicates that both surgery and medical treatment are of considerable value.

Effectiveness of eplerenone or spironolactone treatment in preserving renal function in primary aldosteronism

OBJECTIVE

Primary aldosteronism (PA) has deleterious effects on kidney function independent of blood pressure levels. Up to now, data on effectiveness of different PA therapies regarding renal function are scarce.

DESIGN AND METHODS

This prospective multi-center study included 29 patients with newly diagnosed PA evaluated before and 1 year after treatment initiation, and a second cohort including 119 patients who were evaluated 5.3 and 6.8 years after treatment initiation. Glomerular filtration rate (GFR), spot urine albumin excretion/urinary creatinine (UAE/Ucrea) ratio, biochemical parameters, and 24-h blood pressure were measured. In a larger cross-sectional cohort, renal function was evaluated depending on the type of treatment (adrenalectomy (ADX; n=86); spironolactone (n=65); and eplerenone (n=18)).

RESULTS

GFR and UAE/Ucrea ratio significantly decreased in newly diagnosed PA patients after treatment initiation. In the second cohort, GFR and UAE/Ucrea ratio did not change during study period, and blood pressure was well controlled. In the larger cross-sectional cohort, no differences were seen in GFR and UAE/Ucrea ratio between PA patients on different treatment regimens. However, eplerenone treatment showed lower potassium levels and higher number of required antihypertensive medications.

CONCLUSIONS

Renal dysfunction with elevated albuminuria was seen in PA patients and was reversible after treatment initiation. Medical therapies with spironolactone or eplerenone seem to be as effective as ADX regarding renal function and blood pressure; however, sufficient daily doses need to be given.

Comprehensive re-sequencing of adrenal aldosterone producing lesions reveal three somatic mutations near the KCNJ5 potassium channel selectivity filter

Background

Aldosterone producing lesions are a common cause of hypertension, but genetic alterations for tumorigenesis have been unclear. Recently, either of two recurrent somatic missense mutations (G151R or L168R) was found in the potassium channel KCNJ5 gene in aldosterone producing adenomas. These mutations alter the channel selectivity filter and result in Na⁺ conductance and cell depolarization, stimulating aldosterone production and cell proliferation. Because a similar mutation occurs in a Mendelian form of primary aldosteronism, these mutations appear to be sufficient for cell proliferation and aldosterone production. The prevalence and spectrum of KCNJ5 mutations in different entities of adrenocortical lesions remain to be defined.

Materials and Methods

The coding region and flanking intronic segments of KCNJ5 were subjected to Sanger DNA sequencing in 351 aldosterone producing lesions, from patients with primary aldosteronism and 130 other adrenocortical lesions. The specimens had been collected from 10 different worldwide referral centers.

Results

G151R or L168R somatic mutations were identified in 47% of aldosterone producing adenomas, each with similar frequency. A previously unreported somatic mutation near the selectivity filter, E145Q, was observed twice. Somatic G151R or L168R mutations were also found in 40% of aldosterone producing adenomas associated with marked hyperplasia, but not in specimens with merely unilateral hyperplasia. Mutations were absent in 130 non-aldosterone secreting lesions.

KCNJ5 mutations were overrepresented in aldosterone producing adenomas from female compared to male patients (63 vs. 24%). Males with KCNJ5 mutations were significantly younger than those without (45 vs. 54, respectively; p<0.005) and their APAs with KCNJ5 mutations were larger than those without (27.1 mm vs. 17.1 mm; p<0.005).

Discussion

Either of two somatic KCNJ5 mutations are highly prevalent and specific for aldosterone producing lesions. These findings provide new insight into the pathogenesis of primary aldosteronism.

Oxidative stress-induced glomerular mineralocorticoid receptor activation limits the benefit of salt reduction in Dahl salt-sensitive rats

BACKGROUND

Mineralocorticoid receptor (MR) antagonists attenuate renal injury in salt-sensitive hypertensive rats with low plasma aldosterone levels. We hypothesized that oxidative stress causes MR activation in high-salt-fed Dahl salt-sensitive rats. Furthermore, we determined if MR activation persisted and induced renal injury, even after switching from a high- to a normal-salt diet.

METHODS AND FINDINGS

High-salt feeding for 4 weeks increased dihydroethidium fluorescence (DHE, an oxidant production marker), p22phox (a NADPH oxidase subunit) and serum and glucocorticoid-regulated kinase-1 (SGK1, an MR transcript) in glomeruli, compared with normal-salt feeding, and these changes persisted 4 weeks after salt withdrawal. Tempol treatment (0.5 mmol/L) during high-salt feeding abolished the changes in DHE fluorescence, p22phox and SGK1. Dietary salt reduction after a 4-week high-salt diet decreased both blood pressure and proteinuria, but was associated with significantly higher proteinuria than in normal control rats at 4 weeks after salt reduction. Administration of tempol during high-salt feeding, or eplerenone, an MR antagonist (100 mg/kg/day), started after salt reduction, recovered proteinuria to normal levels at 4 weeks after salt reduction. Paraquat, a reactive oxygen species generator, enhanced MR transcriptional activity in cultured rat mesangial cells and mouse podocytes.

CONCLUSIONS

These results suggest that oxidative stress plays an important role in glomerular MR activation in Dahl salt-sensitive rats. Persistent MR activation even after reducing salt intake could limit the beneficial effects of salt restriction.

Natriuretic peptide receptor guanylyl cyclase-A protects podocytes from aldosterone-induced glomerular injury

Natriuretic peptides produced by the heart in response to cardiac overload exert cardioprotective and renoprotective effects by eliciting natriuresis, reducing BP, and inhibiting cell proliferation and fibrosis. These peptides also antagonize the renin-angiotensin-aldosterone system, but whether this mechanism contributes to their renoprotective effect is unknown. Here, we examined the kidneys of mice lacking the guanylyl cyclase-A (GC-A) receptor for natriuretic peptides under conditions of high aldosterone and high dietary salt. After 4 weeks of administering aldosterone and a high-salt diet, GC-A knockout mice, but not wild-type mice, exhibited accelerated hypertension with massive proteinuria. Aldosterone-infused GC-A knockout mice had marked mesangial expansion, segmental sclerosis, severe podocyte injury, and increased oxidative stress. Reducing the BP with hydralazine failed to lessen such changes; in contrast, blockade of the renin-angiotensin-aldosterone system markedly reduced albuminuria, ameliorated podocyte injury, and reduced oxidative stress. Furthermore, treatment with the antioxidant tempol significantly reduced albuminuria and abrogated the histologic changes. In cultured podocytes, natriuretic peptides inhibited aldosterone-induced mitogen-activated protein kinase phosphorylation. Taken together, these results suggest that renoprotective properties of the endogenous natriuretic peptide/GC-A system may result from the local inhibition of the renin-angiotensin-aldosterone system and oxidative stress in podocytes.

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.

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.

Is salt intake an independent risk factor of stroke mortality? Demographic analysis by regions in Japan

We reported a remarkable regional difference within Japan in the incidence of end-stage renal disease. Regional differences were also well-known for salt intake, blood pressure (BP), and mortality from stroke, which remains one of the leading causes of death. Noting these regional differences, we examined mutual relationships among salt intake, BP, and stroke mortality in 12 regions of Japan. Data of salt intake, BP, and stroke mortality in 12 regions were collected from National Nutrition Survey (NNS-J), reanalysis of NNS-J, and Vital Statistics of National Population Dynamic Survey (Ministry of Health, Labor and Welfare), respectively. Significant regional differences were found in salt intake (P < .0001), mean arterial BP (P = .0001), and stroke mortality (P < .0001). Although annual changes in these parameters were also significant, their regional differences persisted. Salt intake had positive relationships with both mean arterial BP (r = 0.26, P = .0009) and stroke mortality (r = 0.26, P < .0001) across 12 regions, whereas mean arterial BP was not correlated with stroke mortality. Multiple regression analysis further identified salt intake as an independent factor to increase stroke mortality, but mean arterial BP was not a determinant. Compared with the four regions with lowest salt intake, odds ratios of stroke mortality adjusted by mean arterial BP were 1.04 (95% CI, 1.03-1.06) for the intermediate four regions and 1.25 (95% CI, 1.23-1.27) for the four regions with highest salt intake. These findings suggest that salt intake may have an adverse effect on stroke mortality independently of BP.

Diagnosis and treatment of primary aldosteronism

A few simple rules can allow physicians to successfully identify many patients with arterial hypertension caused by PA among the so-called essential hypertensive patients. The hyperaldosteronism and the hypokalemia can be cured with adrenalectomy in practically all of these patients. Moreover, in a substantial proportion of them, the blood pressure can be normalized or markedly lowered if a unilateral cause of PA is discovered. Hence, the screening for PA can be rewarding both for the patient and for the clinician, particularly in those cases where hypertension is severe and/or resistant to treatment, in which the removal of an APA can allow blood pressure to be brought under control despite withdrawal of, or a prominent reduction in, the number and doses of antihypertensive medications.

A comprehensive review of the clinical aspects of primary aldosteronism

Primary aldosteronism is much more common than previously thought. The high prevalence of primary aldosteronism, the damage this condition does to the heart, blood vessels and kidneys (which causes a high rate of cardiovascular events), along with the notion that a timely diagnosis followed by an appropriate therapy can correct the arterial hypertension and hypokalemia, justify efforts to search for primary aldosteronism in many patients with hypertension. Most centers can use a cost-effective strategy to screen for patients with primary aldosteronism. By contrast, the identification of primary aldosteronism subtypes, which involves adrenal-vein sampling, should only be undertaken at tertiary referral centers that have experience in performing and interpreting this test. The identification of a curable form of primary aldosteronism can be beneficial for the patient. In some subgroups of patients with hypertension who are at high risk of primary aldosteronism or can benefit most from an accurate diagnosis, an aggressive diagnostic approach is necessary.

Diagnosis and treatment of primary aldosteronism

Primary aldosteronism involves more than 11% of hypertensive patients who are referred to specialized centers for the diagnosis and treatment of hypertension. If not diagnosed early it causes an excess damage to the heart, vessels and kidney, which translates into an cardiovascular events. Since these ominous consequences can be corrected with a timely diagnosis and an appropriate therapy, physicians should exercise a high degree of alert concerning the possibility that primary aldosteronism is present in hypertensive patients. The purpose of this review is to provide up-dated information on the strategy for case detection, the subtype differentiation and the management of primary aldosteronism.

Guidelines for the diagnosis and treatment of primary aldosteronism--the Japan Endocrine Society 2009

The Japan Endocrine Society (JES) attempted to develop guidelines for the diagnosis and treatment of primary aldosteronism (PA). The Task Force Committee (TFC) was composed of a chair, selected by the JES, and additional experts. Systematic reviews of available evidence for Japanese patients were used to recommend the key treatment and prevention. We have evaluated the methods of screening, confirmatory tests and imaging, plus adrenal vein sampling (AVS). Consensus was guided by systematic review of evidence and discussion during each annual meeting of the JES, plus its related meetings, and by e-mail communication. The drafts prepared by TFC were reviewed successively by the members of Research on Intractable Diseases provided by the Japanese Ministry of Health, Labour and Welfare, and in comments from the JES's councilors. At each stage of review, TFC received written comments and incorporated suggested changes. In conclusion, all patients with hypertension should be screened for PA, because of the high prevalence of cardiovascular disease and the current low case-detection rate in Japan. Case detection can be performed in hypertensive patients and those with hypokalemia by determining the aldosterone/renin ratio, and the diagnosis of PA can be confirmed by two of three confirmatory tests. The presence of a unilateral aldosterone-producing adenoma should be established/excluded by AVS by an experienced radiologist, optimally followed by laparoscopic adrenalectomy. In contrast, patients with bilateral adrenal hyperplasia, or those unsuitable for surgery, are optimally treated medically with mineralocorticoid receptor antagonists.

Pathophysiological roles of aldosterone and mineralocorticoid receptor in the kidney

Aldosterone, a steroid hormone, has traditionally been viewed as a key regulator of fluid and electrolyte homeostasis, as well as blood pressure, through the activation of mineralocorticoid receptor (MR). However, a number of studies performed in the last decade have revealed an important role of aldosterone/MR in the pathogenesis of renal injury. Aldosterone/MR-induced renal tissue injury is associated with increased renal inflammation and oxidative stress, fibrosis, mesangial cell proliferation, and podocyte injury, probably through genomic and non-genomic pathways. However, our preliminary data have indicated that acute administration of aldosterone or a selective MR antagonist, eplerenone, does not change blood pressure, heart rate, or renal blood flow. These data suggest that aldosterone/MR induces renal injury through mechanisms that are independent of acute changes in systemic and renal hemodynamics. In this review, we will briefly summarize the roles of aldosterone/MR in the pathogenesis of renal injury, focusing on the underlying mechanisms that are independent of systemic and renal hemodynamic changes.