Prevalence and clinical correlates of somatic mutation in aldosterone producing adenoma-Taiwanese population

Identifying primary aldosteronism patients who require adrenal venous sampling: a multi-center study

Adrenal venous sampling (AVS) is crucial for subtyping primary aldosteronism (PA) to explore the possibility of curing hypertension. Because AVS availability is limited, efforts have been made to develop strategies to bypass it. However, it has so far proven unsuccessful in applying clinical practice, partly due to heterogeneity and missing values of the cohorts. For this purpose, we retrospectively assessed 210 PA cases from three institutions where segment-selective AVS, which is more accurate and sensitive for detecting PA cases with surgical indications, was available. A machine learning-based classification model featuring a new cross-center domain adaptation capability was developed. The model identified 102 patients with PA who benefited from surgery in the present cohort. A new data imputation technique was used to address cross-center heterogeneity, making a common prediction model applicable across multiple cohorts. Logistic regression demonstrated higher accuracy than Random Forest and Deep Learning [(0.89, 0.86) vs. (0.84, 0.84), (0.82, 0.84) for surgical or medical indications in terms of f-score]. A derived integrated flowchart revealed that 35.2% of PA cases required AVS with 94.1% accuracy. The present model enabled us to reduce the burden of AVS on patients who would benefit the most.

Identifying KCNJ5 Mutation in Aldosterone-Producing Adenoma Patients With Baseline Characteristics Using Machine Learning Technology

Background

Primary aldosteronism is characterized by inappropriate aldosterone production, and unilateral aldosterone-producing adenoma (uPA) is a common type of PA. KCNJ5 mutation is a protective factor in uPA; however, there is no preoperative approach to detect KCNJ5 mutation in patients with uPA.

Objectives

This study aimed to provide a personalized surgical recommendation that enables more confidence in advising patients to pursue surgical treatment.

Methods

We enrolled 328 patients with uPA harboring KCNJ5 mutations (n = 158) or not (n = 170) who had undergone adrenalectomy. Eighty-seven features were collected, including demographics, various blood and urine test results, and clinical comorbidities. We designed 2 versions of the prediction model: one for institutes with complete blood tests (full version), and the other for institutes that may not be equipped with comprehensive testing facilities (condensed version).

Results

The results show that in the full version, the Light Gradient Boosting Machine outperformed other classifiers, achieving area under the curve and accuracy values of 0.905 and 0.864, respectively. The Light Gradient Boosting Machine also showed excellent performance in the condensed version, achieving area under the curve and accuracy values of 0.867 and 0.803, respectively.

Conclusions

We simplified the preoperative diagnosis of KCNJ5 mutations successfully using machine learning. The proposed lightweight tool that requires only baseline characteristics and blood/urine test results can be widely applied and can aid personalized prediction during preoperative counseling for patients with uPA.

Association of urinary liver-type fatty acid-binding protein with outcomes after adrenalectomy for unilateral primary aldosteronism

BACKGROUND AND AIMS

This study explored the association between urinary liver-type fatty acid-binding protein to creatinine (uL-FABP-cre) ratio and postoperative clinical failure in unilateral primary aldosteronism (PA) patients undergoing adrenalectomy.

MATERIALS AND METHODS

Data from the Taiwan Primary Aldosteronism Investigation Group database were analyzed, including patients with unilateral PA who had adrenalectomy between December 2015 and October 2018. Statistical methods included generalized additive modeling, logistic regression analysis, net reclassification improvement (NRI), and the C statistic.

RESULTS

In the study cohort of 131 patients (mean age 52.3 ± 10.8 years; 43.5% male), 117 achieved clinical success, while 14 experienced clinical failure. A uL-FABP-cre ratio ≥5 predicted clinical failure (odds ratio: 6.22, p = 0.005). Subgroup analysis revealed its efficacy in predicting clinical failure in patients with BMI ≥ 24 kg/m2, normokalemia, or <5 years of hypertension. Furthermore, incorporating uL-FABP-cre ratio into the Primary Aldosteronism Surgical Outcome (PASO) score significantly improved predictive ability. The addition increased the C statistic from 0.671 to 0.762 (p < 0.01) and improved category-free NRI by 0.675 (p = 0.014).

CONCLUSION

A uL-FABP-cre ratio ≥5 accurately predicted clinical failure post-adrenalectomy in unilateral PA, enhancing PASO score's identification of high-risk patients for postoperative clinical failure.

Cardiovascular and metabolic characters of KCNJ5 somatic mutations in primary aldosteronism

BACKGROUND

Primary aldosteronism (PA) is the leading cause of curable endocrine hypertension, which is associated with a higher risk of cardiovascular and metabolic insults compared to essential hypertension. Aldosterone-producing adenoma (APA) is a major cause of PA, which can be treated with adrenalectomy. Somatic mutations are the main pathogenesis of aldosterone overproduction in APA, of which KCNJ5 somatic mutations are most common, especially in Asian countries. This article aimed to review the literature on the impacts of KCNJ5 somatic mutations on systemic organ damage.

EVIDENCE ACQUISITION

PubMed literature research using keywords combination, including "aldosterone-producing adenoma," "somatic mutations," "KCNJ5," "organ damage," "cardiovascular," "diastolic function," "metabolic syndrome," "autonomous cortisol secretion," etc.

RESULTS

APA patients with KCNJ5 somatic mutations are generally younger, female, have higher aldosterone levels, lower potassium levels, larger tumor size, and higher hypertension cure rate after adrenalectomy. This review focuses on the cardiovascular and metabolic aspects of KCNJ5 somatic mutations in APA patients, including left ventricular remodeling and diastolic function, abdominal aortic thickness and calcification, arterial stiffness, metabolic syndrome, abdominal adipose tissue, and correlation with autonomous cortisol secretion. Furthermore, we discuss modalities to differentiate the types of mutations before surgery.

CONCLUSION

KCNJ5 somatic mutations in patients with APA had higher left ventricular mass (LVM), more impaired diastolic function, thicker aortic wall, lower incidence of metabolic syndrome, and possibly a lower incidence of concurrent autonomous cortisol secretion, but better improvement in LVM, diastolic function, arterial stiffness, and aortic wall thickness after adrenalectomy compared to patients without KCNJ5 mutations.

Update on the Genetics of Primary Aldosteronism and Aldosterone-Producing Adenomas

PURPOSE OF THE REVIEW

Primary aldosteronism (PA) is the leading cause of secondary hypertension, accounting for over 10% of patients with high blood pressure. It is characterized by autonomous production of aldosterone from the adrenal glands leading to low-renin levels. The two most common forms arise from bilateral adrenocortical hyperplasia (BAH) and aldosterone-producing adenoma (APA). We discuss recent discoveries in the genetics of PA.

RECENT FINDINGS

Most APAs harbor variants in the KCNJ5, CACNA1D, ATP1A1, ATP2B3, and CTNNB1 genes. With the exception of β-catenin (CTNNB1), all other causative genes encode ion channels; pathogenic variants found in PA lead to altered ion transportation, cell membrane depolarization, and consequently aldosterone overproduction. Some of these genes are found mutated in the germline state (CYP11B2, CLCN2, KCNJ5, CACNA1H, and CACNA1D), leading then to familial hyperaldosteronism, and often BAH rather than single APAs. Several genetic defects in the germline or somatic state have been identified in PA. Understanding how these molecular abnormalities lead to excess aldosterone contributes significantly to the elucidation of the pathophysiology of low-renin hypertension. It may also lead to new and more effective therapies for this disease acting at the molecular level.

Clinical Translationality of KCNJ5 Mutation in Aldosterone Producing Adenoma

Hypertension due to primary aldosteronism poses a risk of severe cardiovascular complications compared to essential hypertension. The discovery of the KCNJ5 somatic mutation in aldosteroene producing adenoma (APA) in 2011 and the development of specific CYP11B2 antibodies in 2012 have greatly advanced our understanding of the pathophysiology of primary aldosteronism. In particular, the presence of CYP11B2-positive aldosterone-producing micronodules (APMs) in the adrenal glands of normotensive individuals and the presence of renin-independent aldosterone excess in normotensive subjects demonstrated the continuum of the pathogenesis of PA. Furthermore, among the aldosterone driver mutations which incur excessive aldosterone secretion, KCNJ5 was a major somatic mutation in APA, while CACNA1D is a leading somatic mutation in APMs and idiopathic hyperaldosteronism (IHA), suggesting a distinctive pathogenesis between APA and IHA. Although the functional detail of APMs has not been still uncovered, its impact on the pathogenesis of PA is gradually being revealed. In this review, we summarize the integrated findings regarding APA, APM or diffuse hyperplasia defined by novel CYP11B2, and aldosterone driver mutations. Following this, we discuss the clinical implications of KCNJ5 mutations to support better cardiovascular outcomes of primary aldosteronism.

Evolution of the cardiometabolic profile of primary hyperaldosteronism patients treated with adrenalectomy and with mineralocorticoid receptor antagonists: results from the SPAIN-ALDO Registry

OBJECTIVE

To analyze the evolution of the cardiometabolic profile of patients with primary hyperaldosteronism (PA) after the treatment with surgery and with mineralocorticoid receptor antagonists (MRA).

DESIGN

Retrospective multicentric study of patients with PA on follow-up in twelve Spanish centers between 2018 and 2020.

RESULTS

268 patients with PA treated by surgery (n = 100) or with MRA (n = 168) were included. At baseline, patients treated with surgery were more commonly women (54.6% vs 41.7%, P = 0.042), had a higher prevalence of hypokalemia (72.2% vs 58%, P = 0.022) and lower prevalence of obesity (37.4% vs 51.3%, P = 0.034) than patients treated with MRA. Adrenalectomy resulted in complete biochemical cure in 94.0% and clinical response in 83.0% (complete response in 41.0% and partial response in 42.0%). After a median follow-up of 23.6 (IQR 9.7-53.8) months, the reduction in blood pressure (BP) after treatment was similar between the group of surgery and MRA, but patients surgically treated reduced the number of antihypertensive pills for BP control more than those medically treated (∆antihypertensives: -1.3 ± 1.3 vs 0.0 ± 1.4, P < 0.0001) and experienced a higher increased in serum potassium levels (∆serum potassium: 0.9 ± 0.7 vs 0.6 ± 0.8mEq/ml, P = 0.003). However, no differences in the risk of the onset of new renal and cardiometabolic comorbidities was observed between the group of surgery and MRA (HR = 0.9 [0.5-1.5], P = 0.659).

CONCLUSION

In patients with PA, MRA and surgery offer a similar short-term cardiovascular protection, but surgery improves biochemical control and reduces pill burden more commonly than MRA, and lead to hypertension cure or improvement in up to 83% of the patients.

Divergent Characteristics of T-Cell Receptor Repertoire Between Essential Hypertension and Aldosterone-Producing Adenoma

Aldosterone-producing adenoma (APA) is a benign adrenal tumor that results in persistent hyperaldosteronism. As one major subtype of primary aldosteronism, APA leads to secondary hypertension that is associated with immune dysregulation. However, how the adaptive immune system, particularly the T-cell population, is altered in APA patients remains largely unknown. Here, we performed TCR sequencing to characterize the TCR repertoire between two age-matched groups of patients: one with APA and the other one with essential hypertension (EH). Strikingly, we found a significant reduction of TCR repertoire diversity in the APA group. Analyses on TCR clustering and antigen annotation further showed that the APA group possessed lower diversity in TCR clonotypes with non-common antigen-specific features, compared with the EH group. In addition, our results indicated that the strength of correlation between generation probabilities and frequencies of TCR clonotypes was significantly higher in the APA group than that in the EH group. Finally, we observed that clinical features, including plasma aldosterone level, aldosterone–renin ratio, and blood sodium level, were positively associated with the strength of correlation between generation and abundance of TCR clonotypes in the APA group. Our findings unveiled the correlation between T-cell immune repertoire and APA, suggesting a critical role of such adrenal adenoma in the T-cell immunity of patients with hypertension.

Genetic Alterations in Benign Adrenal Tumors

The genetic basis of most types of adrenal adenomas has been elucidated over the past decade, leading to the association of adrenal gland pathologies with specific molecular defects. Various genetic studies have established links between variants affecting the protein kinase A (PKA) signaling pathway and benign cortisol-producing adrenal lesions. Specifically, genetic alterations in GNAS, PRKAR1A, PRKACA, PRKACB, PDE11A, and PDE8B have been identified. The PKA signaling pathway was initially implicated in the pathogenesis of Cushing syndrome in studies aiming to understand the underlying genetic defects of the rare tumor predisposition syndromes, Carney complex, and McCune-Albright syndrome, both affected by the same pathway. In addition, germline variants in ARMC5 have been identified as a cause of primary bilateral macronodular adrenal hyperplasia. On the other hand, primary aldosteronism can be subclassified into aldosterone-producing adenomas and bilateral idiopathic hyperaldosteronism. Various genes have been reported as causative for benign aldosterone-producing adrenal lesions, including KCNJ5, CACNA1D, CACNA1H, CLCN2, ATP1A1, and ATP2B3. The majority of them encode ion channels or pumps, and genetic alterations lead to ion transport impairment and cell membrane depolarization which further increase aldosterone synthase transcription and aldosterone overproduction though activation of voltage-gated calcium channels and intracellular calcium signaling. In this work, we provide an overview of the genetic causes of benign adrenal tumors.

A Novel Somatic Mutation of CACNA1H p.V1937M in Unilateral Primary Hyperaldosteronism

BACKGROUND

Somatic mutations for excess aldosterone production have been frequently identified as important roles in the pathogenesis of unilateral primary hyperaldosteronism (uPA). Although CACNA1H mutation represents a minor etiology in primary aldosteronism, it plays a significant role in causing uPAs in sporadic cases.

OBJECTIVE

To identify novel somatic CACNA1H mutation in patients with uPA and investigate the pathophysiological, immunohistological, and clinical characteristics of the variant.

METHODS

We applied a customized and targeted gene panel next-generation sequencing approach to detect mutations from the uPA cohort in Taiwan Primary Aldosteronism Investigation study group. Information from pre-diagnostic to postoperative data was collected, including past history, medications, blood pressure readings, biochemical data, and image studies. The functional role of the variant was confirmed by in vitro studies, demonstrating aldosterone production in variant-transfected human adrenal cell lines.

RESULTS

We identified a novel somatic CACNA1H mutation c.5809G>A (p.Val1937Met) in a uPA case. The CACNA1H gene encodes the pore-forming alpha-1H subunit of the voltage-dependent T-type calcium channel Cav3.2. This somatic CACNA1H p.V1937M variant showed excellent clinical and biochemical outcomes after ipsilateral adrenalectomy. The functional effect of somatic CACNA1H p.V1937M variant results in increased CYP11B2 expression and aldosterone biosynthesis in HAC15 cells. A distinct heterogeneous foamy pattern of CYP11B2 and CYP17A1 expression was identified in immunohistological staining, supporting the pathological evidence of aldosterone synthesis.

CONCLUSIONS

The somatic mutation of CACNA1H p.V1937M might be a pathogenic driver in aldosterone overproduction. This study provides new insight into the molecular mechanism and disease outcomes of uPA.

Case Report: Primary Aldosteronism Due to Bilateral Aldosterone-Producing Micronodules With HISTALDO Classical and Contralateral Non-Classical Pathology

BACKGROUND

Non-classical multiple aldosterone-producing micronodules/nodules (mAPM/mAPN) could be the pathogenesis of primary aldosteronism (PA). The co-existence of mAPM with adenomas harboring somatic mutations has not previously been reported.

METHODS

We presented a PA patient with bilateral mAPM and concomitant autonomous cortisol secretion (ACS).

RESULTS

A 46-year-old Taiwanese woman presented with hypertension, hypokalemia, and bilateral adrenal adenomas. A 1 mg low-dose dexamethasone suppression test showed elevated morning serum cortisol. An adrenal vein sampling (AVS) suggested a left-sided lateralization of hyperaldosteronism. A right partial adrenalectomy and a left total adrenalectomy were performed. The patient showed biochemical and hypertension remission after the operation. This patient had bilateral mAPM with concomitant ACS, a right histopathologically classical PA adenoma, and a left non-classical PA adenoma. The right adrenal adenoma showed CYP11B1-negative and CYP11B2-positive staining and harbored the KCNJ5-L168R mutation. The left adrenal adenoma showed CYP11B1-positive and CYP11B2-negative staining and harbored the PRKACA-L206R mutation.

CONCLUSION

In a PA patient with concomitant ACS, bilateral APM could coexist with both histopathologically classical and non-classical PA adenomas, each with different somatic mutations. The presence of ACS could lead to the misinterpretation of AVS results.

Pathogenesis of Primary Aldosteronism: Impact on Clinical Outcome

Primary aldosteronism (PA) is the most common form of secondary arterial hypertension, with a prevalence of approximately 20% in patients with resistant hypertension. In the last decade, somatic pathogenic variants in KCNJ5, CACNA1D, ATP1A1 and ATP2B3 genes, which are involved in maintaining intracellular ionic homeostasis and cell membrane potential, were described in aldosterone-producing adenomas (aldosteronomas). All variants in these genes lead to the activation of calcium signaling, the major trigger for aldosterone production. Genetic causes of familial hyperaldosteronism have been expanded through the report of germline pathogenic variants in KCNJ5, CACNA1H and CLCN2 genes. Moreover, PDE2A and PDE3B variants were associated with bilateral PA and increased the spectrum of genetic etiologies of PA. Of great importance, the genetic investigation of adrenal lesions guided by the CYP11B2 staining strongly changed the landscape of somatic genetic findings of PA. Furthermore, CYP11B2 staining allowed the better characterization of the aldosterone-producing adrenal lesions in unilateral PA. Aldosterone production may occur from multiple sources, such as solitary aldosteronoma or aldosterone-producing nodule (classical histopathology) or clusters of autonomous aldosterone-producing cells without apparent neoplasia denominated aldosterone-producing micronodules (non-classical histopathology). Interestingly, KCNJ5 mutational status and classical histopathology of unilateral PA (aldosteronoma) have emerged as relevant predictors of clinical and biochemical outcome, respectively. In this review, we summarize the most recent advances in the pathogenesis of PA and discuss their impact on clinical outcome.

KCNJ5 Somatic Mutation Is Associated With Higher Aortic Wall Thickness and Less Calcification in Patients With Aldosterone-Producing Adenoma

OBJECTIVE

Primary aldosteronism (PA) is the most common type of secondary hypertension, and it is associated with a higher rate of cardiovascular complications. KCNJ5 somatic mutations have recently been identified in aldosterone-producing adenoma (APA), however their influence on vascular remodeling and injury is still unclear. The aim of this study was to investigate the association between KCNJ5 somatic mutation status and vascular status.

METHODS

We enrolled 179 APA patients who had undergone adrenalectomy from a prospectively maintained database, of whom 99 had KCNJ5 somatic mutations. Preoperative clinical, biochemical and imaging data of abdominal CT, including abdominal aortic calcification (AAC) score, aortic diameter and wall thickness at levels of superior (SMA) and inferior (IMA) mesenteric arteries were analyzed.

RESULTS

After propensity score matching for age, sex, body mass index, triglycerides and low-density lipoprotein, there were 48 patients in each KCNJ5 (+) and KCNJ5 (-) group. Mutation carriers had a lower AAC score (217.3 ± 562.2 vs. 605.6 ± 1359.1, P=0.018), higher aortic wall thickness (SMA level: 2.2 ± 0.6 mm vs. 1.8 ± 0.6 mm, P=0.006; IMA level: 2.4 ± 0.6 mm vs. 1.8 ± 0.7 mm, P<0.001) than non-carriers. In multivariate analysis, KCNJ5 mutations were independently associated with AAC score (P=0.014) and aortic wall thickness (SMA level: P<0.001; IMA level: P=0.004). After adrenalectomy, mutation carriers had less aortic wall thickness progression than non-carriers (Δthickness SMA: -0.1 ± 0.8 mm vs. 0.9 ± 0.6 mm, P=0.024; IMA: -0.1 ± 0.6 mm vs. 0.8 ± 0.7 mm, P=0.04).

CONCLUSION

KCNJ5 mutation carriers had less calcification burden of the aorta, thickened aortic wall, and less wall thickness progression than non-carriers.

Disorders of the adrenal cortex: Genetic and molecular aspects

Adrenal cortex produces glucocorticoids, mineralocorticoids and adrenal androgens which are essential for life, supporting balance, immune response and sexual maturation. Adrenocortical tumors and hyperplasias are a heterogenous group of adrenal disorders and they can be either sporadic or familial. Adrenocortical cancer is a rare and aggressive malignancy, and it is associated with poor prognosis. With the advance of next-generation sequencing technologies and improvement of genomic data analysis over the past decade, various genetic defects, either from germline or somatic origin, have been unraveled, improving diagnosis and treatment of numerous genetic disorders, including adrenocortical diseases. This review gives an overview of disorders associated with the adrenal cortex, the genetic factors of these disorders and their molecular implications.

Characteristics of a Novel ATP2B3 K416_F418delinsN Mutation in a Classical Aldosterone-Producing Adenoma

Simple Summary

The ATP2B3 channel mutation is a rare cause of primary aldosteronism (PA). ATP2B3 gene mutation leads to the dysfunction of calcium channel that pumps calcium ion out of the cell and accumulates intracellular calcium signal to stimulate aldosterone synthesis. In the present study, we found a novel somatic ATP2B3 K416_F418delinsN mutation in a PA patient, and proved its functionality by demonstrating aldosterone hyper-function in the mutant-transfected adrenal cell-line. The ATP2B3 K416_F418delinsN mutation resulted from the deletion from nucleotides 1248 to 1253. The translated amino acid sequence from 416 to 418 as lysine-phenylalanine-phenylalanine was deleted and an asparagine was inserted due to the merging of residual nucleotide sequences.

Abstract

In patients with primary aldosteronism (PA), the prevalence of ATP2B3 mutation is rare. The aim of this study is to report a novel ATP2B3 mutation in a PA patient. Based on our tissue bank of aldosterone-producing adenomas (APA), we identified a novel somatic ATP2B3 K416_F418delinsN mutation. The affected individual was a 53 year-old man with a 4 year history of hypertension. Computed tomography (CT) showed bilateral adrenal masses of 1.6 (left) and 0.5 cm (right) in size. An adrenal venous sampling (AVS) showed a lateralization index (LI) of 2.2 and a contralateral suppression index (CLS) of 0.12; indicating left functional predominance. After a left unilateral adrenalectomy, he achieved partial biochemical and hypertension–remission. This classical adenoma harbored a novel ATP2B3 K416_F418delinsN somatic mutation, which is a deletion from nucleotides 1248 to 1253. The translated amino acid sequence from 416 to 418, reading as lysine-phenylalanine-phenylalanine, was deleted; however, an asparagine was inserted due to merging of residual nucleotide sequences. The CYP11B2 immunohistochemistry staining demonstrated strong immunoreactivity in this classical adenoma. The ATP2B3 K416_F418delinsN mutation is a functional mutation in APA, since HAC15 cells, a human adrenal cell line, transfected with the mutant gene showed increased CYP11B2 expression and aldosterone production.

KCNJ5 Somatic Mutations in Aldosterone-Producing Adenoma Are Associated with a Greater Recovery of Arterial Stiffness

Simple Summary

Primary aldosteronism (PA) is the most common form of secondary hypertension and induces various cardiovascular injuries. Aldosterone-producing adenoma (APA) is one of the major forms of PA. The occurrence of APA is closely correlated with somatic mutations, including KCNJ5. We described here the impact of KCNJ5 somatic mutations on arterial stiffness excluding the influence of age, sex, and blood pressure status. We found KCNJ5 mutation carriers had similar arterial stiffness before surgery, but greater improvement of arterial stiffness after adrenalectomy compared with non-carriers. Hence, APA patients with KCNJ5 mutations had a greater improvement in arterial stiffness after adrenalectomy than those without mutations.

Abstract

Primary aldosteronism is the most common form of secondary hypertension and induces various cardiovascular injuries. In aldosterone-producing adenoma (APA), the impact of KCNJ5 somatic mutations on arterial stiffness excluding the influence of confounding factors is uncertain. We enrolled 213 APA patients who were scheduled to undergo adrenalectomy. KCNJ5 gene sequencing of APA was performed. After propensity score matching (PSM) for age, sex, body mass index, blood pressure, number of hypertensive medications, and hypertension duration, there were 66 patients in each group with and without KCNJ5 mutations. The mutation carriers had a higher aldosterone level and lower log transformed brachial–ankle pulse wave velocity (baPWV) than the non-carriers before PSM, but no difference in log baPWV after PSM. One year after adrenalectomy, the mutation carriers had greater decreases in log plasma aldosterone concentration, log aldosterone–renin activity ratio, and log baPWV than the non-carriers after PSM. Only the mutation carriers had a significant decrease in log baPWV after surgery both before and after PSM. KCNJ5 mutations were not correlated with baseline baPWV after PSM but were significantly correlated with ∆baPWV after surgery both before and after PSM. Conclusively, APA patients with KCNJ5 mutations had a greater regression in arterial stiffness after adrenalectomy than those without mutations.

Pathophysiological and Pharmacological Characteristics of KCNJ5 157-159delITE Somatic Mutation in Aldosterone-Producing Adenomas

Mutated channelopathy could play important roles in the pathogenesis of aldosterone-producing adenoma (APA). In this study, we identified a somatic mutation, KCNJ5 157-159delITE, and reported its immunohistological, pathophysiological and pharmacological characteristics. We conducted patch-clamp experiments on HEK293T cells and experiments on expression of aldosterone synthase (CYP11B2) and aldosterone secretion in HAC15 cells to evaluate electrophysiological and functional properties of this mutated KCNJ5. Immunohistochemistry was conducted to identify expressions of several steroidogenic enzymes. Macrolide antibiotics and a calcium channel blocker were administrated to evaluate the functional attenuation of mutated KCNJ5 channel in transfected HAC15 cells. The interaction between macrolides and KCNJ5 protein was evaluated via molecular docking and molecular dynamics simulation analysis. The immunohistochemistry analysis showed strong CYP11B2 immunoreactivity in the APA harboring KCNJ5 157-159delITE mutation. Whole-cell patch-clamp data revealed that mutated KCNJ5 157-159delITE channel exhibited loss of potassium ion selectivity. The mutant-transfected HAC15 cells increased the expression of CYP11B2 and aldosterone secretion, which was partially suppressed by clarithromycin and nifedipine but not roxithromycin treatment. The docking analysis and molecular dynamics simulation disclosed that roxithromycin had strong interaction with KCNJ5 L168R mutant channel but not with this KCNJ5 157-159delITE mutant channel. We showed comprehensive evaluations of the KCNJ5 157-159delITE mutation which revealed that it disrupted potassium channel selectivity and aggravated autonomous aldosterone production. We further demonstrated that macrolide antibiotics, roxithromycin, could not interfere the aberrant electrophysiological properties and gain-of-function aldosterone secretion induced by KCNJ5 157-159delITE mutation.

Aldosterone-producing adenoma-harbouring KCNJ5 mutations is associated with lower prevalence of metabolic disorders and abdominal obesity

OBJECTIVE

Aldosterone overproduction and lipid metabolic disturbances between idiopathic hyperaldosteronism (IHA) and unilateral aldosterone-producing adenoma (APA) have been inconsistently linked in patients with primary aldosteronism. Moreover, KCNJ5 mutations are prevalent among APAs and enhance aldosterone synthesis in adrenal cortex. We aimed to investigate the prevalence of metabolic syndrome (MetS) in each primary aldosteronism subtype and observe the role of KCNJ5 mutations among APAs on the distribution of abdominal adipose tissues quantified using computed tomography (CT), including their changes postadrenalectomy.

DESIGN AND METHODS

We retrospectively collected 244 and 177 patients with IHA and APA at baseline. Patients with APA had undergone adrenalectomy, and gene sequencing revealed the absence (n = 75) and presence (n = 102) of KCNJ5 mutations. We also recruited 31 patients with APA who had undergone CT-scan 1-year postadrenalectomy.

RESULTS

The patients with APA harbouring KCNJ5 mutations had significantly lower prevalence of MetS and smaller distribution in waist circumference, subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) than the other groups. Logistic regression analysis indicated that the VAT area correlated significantly with KCNJ5 mutations among the APAs. Only participants with KCNJ5 mutations had significant increases in triglycerides, cholesterol, SAT, and VAT after 1-year postadrenalectomy.

CONCLUSION

This study is the first to demonstrate that MetS and abdominal obesity were less prevalent in the patients with APA harbouring KCNJ5 mutations compared with the IHA group and the non-KCNJ5-mutated APA group. Increasing prevalence of dyslipidaemia and abdominal obesity was observed in patients with KCNJ5 mutations 1-year postadrenalectomy.

Diseases caused by mutations in the Na+/K+ pump α1 gene ATP1A1

Human cell survival requires function of the Na⁺/K⁺ pump; the heteromeric protein that hydrolyzes ATP to extrude Na⁺ and import K⁺ across the plasmalemma, thereby building and maintaining these ions' electrochemical gradients. Numerous dominant diseases caused by mutations in genes encoding for Na⁺/K⁺ pump catalytic (α) subunit isoforms highlight the importance of this protein. Here, we review literature describing disorders caused by missense mutations in ATP1A1, the gene encoding the ubiquitously expressed α1 isoform of the Na⁺/K⁺ pump. These various maladies include primary aldosteronism with secondary hypertension, an endocrine syndrome, Charcot-Marie-Tooth disease, a peripheral neuropathy, complex spastic paraplegia, another neuromuscular disorder, as well as hypomagnesemia accompanied by seizures and cognitive delay, a condition affecting the renal and central nervous systems. This article focuses on observed commonalities among these mutations' functional effects, as well as on the special characteristics that enable each particular mutation to exclusively affect a certain system, without affecting others. In this respect, it is clear how somatic mutations localized to adrenal adenomas increase aldosterone production without compromising other systems. However, it remains largely unknown how and why some but not all de novo germline or familial mutations (where the mutant must be expressed in numerous tissues) produce a specific disease and not the other diseases. We propose hypotheses to explain this observation and the approaches that we think will drive future research on these debilitating disorders to develop novel patient-specific treatments by combining the use of heterologous protein-expression systems, patient-derived pluripotent cells, and gene-edited cell and mouse models.

GENETICS IN ENDOCRINOLOGY: Impact of race and sex on genetic causes of aldosterone-producing adenomas

Primary aldosteronism (PA) is a common cause of secondary hypertension. Recent technological advances in genetic analysis have provided a better understanding of the molecular pathogenesis of this disease. The application of next-generation sequencing has resulted in the identification of somatic mutations in aldosterone-producing adenoma (APA), a major subtype of PA. Based on the recent findings using a sequencing method that selectively targets the tumor region where aldosterone synthase (CYP11B2) is expressed, the vast majority of APAs appear to harbor a somatic mutation in one of the aldosterone-driver genes, including KCNJ5, ATP1A1, ATP2B3, CACNA1D, CACNA1H, and CLCN2. Mutations in these genes alter intracellular ion homeostasis and enhance aldosterone production. In a small subset of APAs, somatic activating mutations in the CTNNB1 gene, which encodes β-catenin, have also been detected. Accumulating evidence suggests that race and sex impact the somatic mutation spectrum of APA. Specifically, somatic mutations in the KCNJ5 gene, encoding an inwardly rectifying K+ channel, are common in APAs from Asian populations as well as women regardless of race. Associations between APA histology, genotype, and patient clinical characteristics have also been proposed, suggesting a potential need to consider race and sex for the management of PA patients. Herein, we review recent findings regarding somatic mutations in APA and discuss potential roles of race and sex on the pathophysiology of APA as well as possible clinical implications.

Taiwan mini-frontier of primary aldosteronism: Updating treatment and comorbidities detection

The aim of this study was to update the information on internationally acceptable standards and clinical practice recommendations for the management of patients with primary aldosteronism (PA). The Taiwan Society of Aldosteronism (TSA) Task Force acknowledged the novel issues of PA and reached a group consensus on PA in Taiwan by collecting the best available evidence and conducting one group meeting, several conference calls, and multiple e-mail communications. Unilateral adrenalectomy is the preferred treatment for patients with aldosterone-producing adenoma (APA). For medical treatment with mineralocorticoid receptor antagonists (MRAs), spironolactone is the first-line treatment, and eplerenone is a reasonable alternative in PA patients intolerant or contraindicated to spironolactone. The dose of MRAs can be titrated according to plasma renin activity (PRA). For screening PA-related comorbidities, we suggest albuminuria to predict a post-treatment decline in renal function, echocardiography as cardiac evaluation, bone mineral density scan for osteoporosis, and obstructive sleep apnea. In tissue and genetic surveys, we suggest immunohistochemical staining and somatic mutation screening for post-operative adrenal specimens in APA patients. With this consensus, we hope to update the information on PA for clinical physicians to facilitate better identification, management and treatment of patients with PA.

Update on Genetics of Primary Aldosteronism

Primary aldosteronism (PA) is the most common form of secondary hypertension, with a prevalence of 5–10% among patients with hypertension. PA is mainly classified into two subtypes: aldosterone-producing adenoma (APA) and bilateral idiopathic hyperaldosteronism. Recent developments in genetic analysis have facilitated the discovery of mutations in KCNJ5, ATP1A1, ATP2B3, CACNA1D, CACNA1H, CLCN2, and CTNNB1 in sporadic or familial forms of PA in the last decade. These findings have greatly advanced our understanding of the mechanism of excess aldosterone synthesis, particularly in APA. Most of the causative genes encode ion channels or pumps, and their mutations lead to depolarization of the cell membrane due to impairment of ion transport. Depolarization activates voltage-gated Ca²⁺ channels and intracellular calcium signaling and promotes the transcription of aldosterone synthase, resulting in overproduction of aldosterone. In this article, we review recent findings on the genetic and molecular mechanisms of PA.

Unravelling the Genetic Basis of Primary Aldosteronism

Primary aldosteronism (PA), a condition characterized by autonomous aldosterone hypersecretion, constitutes the most common cause of secondary hypertension. Over the last decade, major breakthroughs have been made in the field of genetics underpinning PA. The advent and wide application of Next Generation Sequencing (NGS) technology led to the identification of several somatic and germline mutations associated with sporadic and familial forms of PA. Somatic mutations in ion-channel genes that participate in aldosterone biosynthesis, including KCNJ5, CACNA1D, ATP1A1, and ATP2B3, have been implicated in the development of aldosterone-producing adenomas (APAs). On the other hand, germline variants in CLCN2, KCNJ5, CACNA1H, and CACNA1D genes have been implicated in the pathogenesis of the familial forms of PA, FH-II, FH-III, and F-IV, as well as PA associated with seizures and neurological abnormalities. However, recent studies have shown that the prevalence of PA is higher than previously thought, indicating the need for an improvement of our diagnostic tools. Further research is required to recognize mild forms of PA and to investigate the underlying molecular mechanisms.

Urinary sodium potassium ratio is associated with clinical success after adrenalectomy in patients with unilateral primary aldosteronism

Background

The urinary sodium potassium (NaK) ratio is associated with dietary sodium and potassium intake and blood pressure, and it also reflects the activity of aldosterone. Herein we evaluated the value of the urinary NaK ratio in predicting the surgical outcomes of patients with unilateral primary aldosteronism (uPA).

Methods

This non-concurrent prospective cohort study was conducted from 2011 to 2017 and included 241 uPA patients who had undergone adrenalectomy. Predictors of successful clinical outcomes were analyzed using logistic regression.

Results

Among the 241 uPA patients, 197 (81.7%) achieved clinical complete or partial success. A urinary sodium potassium ratio <3 (odds ratio (OR): 2.5; 95% confidence interval (CI): 1.2-5.4; p = 0.015), body mass index <25 kg/m² (OR: 2.82; 95% CI: 1.31-6.06; p = 0.008), renin <1 ng/mL/h (OR: 2.51; 95% CI: 1.01-6.21; p = 0.047) and mean preoperative blood pressure >115 mmHg (OR: 5.02; 95% CI: 2.10-11.97; p < 0.001) could predict clinical success after adrenalectomy. Furthermore, higher pre-treatment plasma aldosterone (OR: 1.014; 95% CI 1.005-1.024; p = 0.002) or lower serum potassium (OR: 0.523; 95% CI: 0.328-0.836; p = 0.007) were correlated with lower urinary NaK ratio (<3), and log urinary NaK ratio was positively correlated with serum C-reactive protein (β value 2.326; 95% CI 0.029-4.623; p = 0.047).

Conclusions

uPA patients with a lower urinary NaK ratio, due to high plasma aldosterone and low serum potassium concentrations, were more likely to have clinical success after adrenalectomy. uPA patients with a higher urinary NaK ratio were associated with more severe inflammatory status, and possibly more resistant hypertension post-operatively.

Approaches to Gene Mutation Analysis Using Formalin-Fixed Paraffin-Embedded Adrenal Tumor Tissue From Patients With Primary Aldosteronism

Aldosterone production is physiologically under the control of circulating potassium and angiotensin II as well as adrenocorticotropic hormone and other secretagogues such as serotonin. The adrenal's capacity to produce aldosterone relies heavily on the expression of a single enzyme, aldosterone synthase (CYP11B2). This enzyme carries out the final reactions in the synthesis of aldosterone and is expressed almost solely in the adrenal zona glomerulosa. From a disease standpoint, primary aldosteronism (PA) is the most common of all adrenal disorders. PA results from renin-independent adrenal expression of CYP11B2 and production of aldosterone. The major causes of PA are adrenal aldosterone-producing adenomas (APA) and adrenal idiopathic hyperaldosteronism. Our understanding of the genetic causes of APA has significantly improved through comprehensive genetic profiling with next-generation sequencing. Whole-exome sequencing has led to the discovery of mutations in six genes that cause renin-independent aldosterone production and thus PA. To facilitate broad-based prospective and retrospective studies of APA, recent technologic advancements have allowed the determination of tumor mutation status using formalin-fixed paraffin-embedded (FFPE) tissue sections. This approach has the advantages of providing ready access to archival samples and allowing CYP11B2 immunohistochemistry-guided capture of the exact tissue responsible for inappropriate aldosterone synthesis. Herein we review the methods and approaches that facilitate the use of adrenal FFPE material for DNA capture, sequencing, and mutation determination.

Molecular Genetic and Genomic Alterations in Cushing's Syndrome and Primary Aldosteronism

The genetic alterations that cause the development of glucocorticoid and/or mineralocorticoid producing benign adrenocortical tumors and hyperplasias have largely been elucidated over the past two decades through advances in genomics. In benign aldosterone-producing adrenocortical tumors and hyperplasias, alteration of intracellular calcium signaling has been found to be significant in aldosterone hypersecretion, with causative defects including those in KCNJ5, ATP1A1, ATP2B3, CACNA1D, CACNA1H, and CLCN2. In benign cortisol-producing adrenocortical tumors and hyperplasias abnormal cyclic adenosine monophosphate-protein kinase A signaling has been found to play a central role in tumorigenesis, with pathogenic variants in GNAS, PRKAR1A, PRKACA, PRKACB, PDE11A, and PDE8B being implicated. The role of this signaling pathway in the development of Cushing's syndrome and adrenocortical tumors was initially discovered through the study of the underlying genetic defects causing the rare multiple endocrine neoplasia syndromes McCune-Albright syndrome and Carney complex with subsequent identification of defects in genes affecting the cyclic adenosine monophosphate-protein kinase A pathway in sporadic tumors. Additionally, germline pathogenic variants in ARMC5, a putative tumor suppressor, were found to be a cause of cortisol-producing primary bilateral macronodular adrenal hyperplasia. This review describes the genetic causes of benign cortisol- and aldosterone-producing adrenocortical tumors.

NP-59 Adrenal Scintigraphy as an Imaging Biomarker to Predict KCNJ5 Mutation in Primary Aldosteronism Patients

PURPOSE

Somatic KCNJ5 mutation occurs in half of unilateral primary aldosteronism (PA) and is associated with more severe phenotype. Mutation status can only be identified by tissue sample from adrenalectomy. NP-59 adrenal scintigraphy is a noninvasive functional study for disease activity assessment. This study aimed to evaluate the predictive value of NP-59 adrenal scintigraphy in somatic KCNJ5 mutation among PA patients who received adrenalectomy.

METHODS

Sixty-two PA patients who had NP-59 adrenal scintigraphy before adrenalectomy with available KCNJ5 mutation status were included. Two semiquantitative parameters, adrenal to liver ratio (ALR) and lesion to contralateral ratio of bilateral adrenal glands (CON) derived from NP-59 adrenal scintigraphy, of mutated and wild-type patients were compared. Cutoff values calculated by receiver-operating characteristic (ROC) analysis were used as a predictor of KCNJ5 mutation.

RESULTS

Twenty patients had KCNJ5 mutation and 42 patients were wild type. Patients harboring KCNJ5 mutation had both higher ALR and CON (p = 0.0031 and 0.0833, respectively) than wild-type patients. With ALR and CON cutoff of 2.10 and 1.95, the sensitivity and specificity to predict KCNJ5 mutation were 85%, 57% and 45%, 93%, respectively. Among 20 patients with KCNJ5 mutation, 16 showed G151R point mutation (KCNJ5- G151R) and 4 showed L168R point mutation (KCNJ5-L168R), which former one had significantly lower ALR (p=0.0471).

CONCLUSION

PA patients harboring somatic KCNJ5 mutation had significantly higher NP-59 uptake regarding to ALR and CON than those without mutation. APAs with KCNJ5-L168R point mutation showed significantly higher ALR than those with KCNJ5-G151R point mutation.

KCNJ5 Somatic Mutations in Aldosterone-Producing Adenoma Are Associated With a Worse Baseline Status and Better Recovery of Left Ventricular Remodeling and Diastolic Function

Primary aldosteronism is the most common secondary endocrine form of hypertension and causes many cardiovascular injuries. KCNJ5 somatic mutations have recently been identified in aldosterone-producing adenoma. However, their impacts on left ventricular remodeling precluding the interference of age, sex, and blood pressure are still uncertain. We enrolled 184 aldosterone-producing adenoma patients who received adrenalectomy. Clinical, biochemical, and echocardiographic data were analyzed preoperatively and 1 year postoperatively. KCNJ5 gene sequencing of aldosterone-producing adenoma was performed. After propensity score matching for age, sex, body mass index, blood pressure, hypertension duration, and number of hypertensive medications, there were 60 patients in each group with and without KCNJ5 mutations. The mutation carriers had higher left ventricular mass index (LVMI) and inappropriately excessive LVMI (ieLVMI) and lower e' than the noncarriers. After adrenalectomy, the mutation carriers had greater decreases in LVMI and ieLVMI than the noncarriers. In addition, only mutation carriers had a significant decrease in E/e' after surgery. In multivariate analysis, baseline LVMI correlated with KCNJ5 mutations, the number of hypertensive medications, and systolic blood pressure. Baseline ieLVMI correlated with KCNJ5 mutations and the number of hypertensive medications. The regression of both LVMI and ieLVMI after surgery was mainly correlated with KCNJ5 mutations and changes in systolic blood pressure. Aldosterone-producing adenoma patients with KCNJ5 mutations had higher LVMI and ieLVMI and a greater regression of LVMI and ieLVMI after adrenalectomy than those without mutations. The patients with KCNJ5 mutations also benefited from adrenalectomy with regard to left ventricular diastolic function, whereas noncarriers did not.

Arterial Stiffness Is Associated with Clinical Outcome and Cardiorenal Injury in Lateralized Primary Aldosteronism

CONTEXT

The association between arterial stiffness and clinical outcome in lateralized primary aldosteronism (PA) patients after adrenalectomy has not been clearly identified.

OBJECTIVE

We hypothesized that arterial stiffness estimated by brachial-ankle pulse wave velocity (baPWV) before adrenalectomy was associated with the clinical outcomes and cardiorenal injury in lateralized PA patients after adrenalectomy.

DESIGN AND PATIENTS

We designed a retrospective observational cohort study. We collected lateralized PA patients who had undergone adrenalectomy between 2013 and 2016 from the Taiwan Primary Aldosteronism Investigation database. The primary outcome was achieving complete clinical success at 1 year after adrenalectomy. The secondary outcome was estimated glomerular filtration rate declining over 20% and improved left ventricular mass index.

RESULTS

We enrolled 221 patients with lateralized PA (50.7% men; mean age, 51.9 years), of whom 101 patients (45.7%) achieved complete clinical success at the 1-year follow-up assessment after adrenalectomy. Lower baPWV before adrenalectomy (odds ratio = 0.998; 95% confidence interval, 0.996-0.999; P = 0.003) correlated with higher likelihood of complete clinical success by multivariate logistic regression analysis. Multifactorial adjusted generalized additive model demonstrated that preoperative baPWV<1600 cm/sec was significantly associated with complete cure of hypertension. In addition, higher preoperative baPWV was associated with renal function decline and less left ventricular mass regression after adrenalectomy in lateralized PA patients during the follow-up period.

CONCLUSIONS

Our study demonstrated that the preoperative severe arterial stiffness was associated with absent complete clinical success in lateralized PA patients after adrenalectomy, and this effect may contribute to cardiorenal injury, which at least partially explains kidney function deterioration and lessened regression of heart mass.

Hyperaldosteronism: How Current Concepts Are Transforming the Diagnostic and Therapeutic Paradigm

Nearly seven decades have elapsed since the clinical and biochemical features of primary hyperaldosteronism (PA) were described by Conn. PA is now widely recognized as the most common form of secondary hypertension. PA has a strong correlation with cardiovascular disease and failure to recognize and/or properly diagnose this condition has profound health consequences. With proper identification and management, PA has the potential to be surgically cured in a proportion of affected individuals. The diagnostic pursuit for PA is not a simplistic endeavor, particularly because an enhanced understanding of the disease process is continually redefining the diagnostic and treatment algorithm. These new concepts have emerged in all areas of this clinical condition, including identification, diagnosis, and treatment. Here, we review the recent advances in this field and summarize the effect these advances have on both diagnostic and therapeutic modalities.

Transtubular potassium gradient predicts kidney function impairment after adrenalectomy in primary aldosteronism

Background:

In primary aldosteronism (PA), kidney function impairment could be concealed by relative hyperfiltration and emerge after adrenalectomy. We hypothesized transtubular gradient potassium gradient (TTKG), a kidney aldosterone bioactivity indicator, could correlate to end organ damage and forecast kidney function impairment after adrenalectomy.

Methods:

In the present prospective study, we enrolled lateralized PA patients who underwent adrenalectomy and were followed up 12 months after operation in the Taiwan Primary Aldosteronism Investigation (TAIPAI) registry from 2010 to 2018. The clinical outcome was kidney function impairment, defined as estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m² at 12 months after adrenalectomy. End organ damage is determined by microalbuminuria and left ventricular mass.

Results:

In total, 323 patients [mean, 50.8 ± 10.9 years old; female 178 (55.1%)] were enrolled. Comparing pre-operation and post-operation data, systolic blood pressure, serum aldosterone, urinary albumin to creatinine ratio and eGFR decreased. TTKG ⩾ 4.9 correlated with pre-operative urinary albumin to creatinine ratio >50 mg/g [odds ratio (OR) = 2.42; p = 0.034] and left ventricular mass (B = 20.10; p = 0.018). Multivariate logistic regression analysis demonstrated that TTKG ⩾ 4.9 could predict concealed chronic kidney disease (OR = 5.42; p = 0.011) and clinical success (OR = 2.90, p = 0.017) at 12 months after adrenalectomy.

Conclusions:

TTKG could predict concealed kidney function impairment and cure of hypertension in PA patients after adrenalectomy. TTKG more than 4.9 as an adverse surrogate of aldosterone and hypokalaemia correlated with pre-operative end organ damage in terms of high proteinuria and cardiac hypertrophy.

Presence of Subclinical Hypercortisolism in Clinical Aldosterone-Producing Adenomas Predicts Lower Clinical Success

The clinical characteristics and outcomes in patients with clinical aldosterone-producing adenomas harboring KCNJ5 mutations with or without subclinical hypercortisolism remain unclear. This prospective study is aimed at determining factors associated with subclinical hypercortisolism in patients with clinical aldosterone-producing adenomas. Totally, 82 patients were recruited from November 2016 to March 2018 and underwent unilateral laparoscopic adrenalectomy with at least a 12-month follow-up postoperatively. Standard subclinical hypercortisolism (defined as cortisol >1.8 μg/dL after 1 mg dexamethasone suppression test [DST]) was detected in 22 (26.8%) of the 82 patients. Intriguingly, a generalized additive model identified the clinical aldosterone-producing adenoma patients with 1 mg DST>1.5 μg/dL had significantly larger tumors (P=0.02) than those with 1 mg DST<1.5 μg/dL. Multivariable logistic regression showed that the presence of KCNJ5 mutations (odds ratio, 0.22, P=0.010) and body mass index (odds ratio, 0.87, P=0.046) were negatively associated with 1 mg DST>1.5 μg/dL, whereas tumor size was positively associated with it (odds ratio, 2.85, P=0.014). Immunohistochemistry revealed a higher degree of immunoreactivity for CYP11B1 in adenomas with wild-type KCNJ5 (P=0.018), whereas CYP11B2 was more commonly detected in adenomas with KCNJ5 mutation (P=0.007). Patients with wild-type KCNJ5 and 1 mg DST>1.5 μg/dL exhibited the lowest complete clinical success rate (36.8%) after adrenalectomy. In conclusion, subclinical hypercortisolism is common in clinical aldosterone-producing adenoma patients without KCNJ5 mutation or with a relatively larger adrenal tumor. The presence of serum cortisol levels >1.5 μg/dL after 1 mg DST may be linked to a lower clinical complete success rate.

Adrenocortical tumorigenesis: Lessons from genetics

Advances in genomics over the past two decades have allowed for elucidation of the genetic alterations leading to the development of adrenocortical tumors and/or hyperplasias. These molecular changes were initially discovered through the study of rare familial tumor syndromes such as McCune-Albright Syndrome, Carney complex, Li-Fraumeni syndrome, and Beckwith-Wiedemann syndrome, with the identification of alterations in genes and molecular pathways that subsequently led to the discovery of aberrations in these or related genes and pathways in sporadic tumors. Genetic alterations in GNAS, PRKAR1A, PRKACA, PRKACB, PDE11A, and PDE8B, that lead to aberrant cyclic adenosine monophosphate-protein (cAMP) kinase A signaling, were found to play a major role in the development of benign cortisol-producing adrenocortical tumors and/or hyperplasias, whereas genetic defects in KCNJ5, ATP1A1, ATP2B3, CACNA1D, CACNA1H, and CLCN2 were implicated in the development of benign aldosterone-producing tumors and/or hyperplasias through modification of intracellular calcium signaling. Germline ARMC5 defects were found to cause the development of primary bilateral macronodular adrenocortical hyperplasia with glucocorticoid and/or mineralocorticoid oversecretion. Adrenocortical carcinoma was linked primarily to aberrant p53 signaling and/or Wnt-β-catenin signaling, as well as IGF2 overexpression, with frequent genetic alterations in TP53, ZNRF3, CTNNB1, and 11p15. This review focuses on the genetic underpinnings of benign cortisol- and aldosterone-producing adrenocortical tumors/hyperplasias and adrenocortical carcinoma.

Primary aldosteronism diagnostics: KCNJ5 mutations and hybrid steroid synthesis in aldosterone-producing adenomas

Primary aldosteronism (PA) is characterized by autonomous aldosterone production by renin-independent mechanisms and is most commonly sporadic. While 60-70% of sporadic PA can be attributed to bilateral hyperaldosteronism, the remaining 30-40% is caused by a unilateral aldosterone-producing adenoma (APA). Somatic mutations in or near the selectivity filter the KCNJ5 gene (encoding the potassium channel GIRK4) have been implicated in the pathogenesis of both sporadic and familial PA. Several studies using tumor tissue, peripheral and adrenal vein samples from PA patients have demonstrated that along with aldosterone, the hybrid steroids 18-hydroxycortisol (18OHF) and 18-oxocortisol (18oxoF) are a hallmark of APA harboring KCNJ5 mutations. Herein, we review the recent advances with respect to the molecular mechanisms underlying the pathogenesis of PA and the steroidogenic fingerprints of KCNJ5 mutations. In addition, we present an outlook toward the future of PA subtyping and diagnostic work-up utilizing steroid profiling.

Old and new genes in primary aldosteronism

Primary aldosteronism (PA) is the most common form of secondary hypertension affecting 5%-10% of patients with arterial hypertension. In PA, high blood pressure is associated with high aldosterone and low renin levels, and often hypokalemia. In a majority of cases, autonomous aldosterone production by the adrenal gland is caused by an aldosterone producing adenoma (APA) or bilateral adrenal hyperplasia (BAH). During the last ten years, a better knowledge of the pathophysiology of PA came from the discovery of somatic and germline mutations in different genes in both sporadic and familial forms of the disease. Those genes code for ion channels and pumps, as well as proteins involved in adrenal cortex development and function. Targeted next generation sequencing following immunohistochemistry guided detection of aldosterone synthase expression allows detection of somatic mutations in up to 90% of APA, while whole exome sequencing has discovered the genetic causes of four different familial forms of PA. The identification, in BAH, of somatic mutations in aldosterone producing cell clusters open new perspectives in our understanding of the bilateral form of the disease and the development of new therapeutic approaches.

Genetic causes of primary aldosteronism

Primary aldosteronism is characterized by at least partially autonomous production of the adrenal steroid hormone aldosterone and is the most common cause of secondary hypertension. The most frequent subforms are idiopathic hyperaldosteronism and aldosterone-producing adenoma. Rare causes include unilateral hyperplasia, adrenocortical carcinoma and Mendelian forms (familial hyperaldosteronism). Studies conducted in the last eight years have identified somatic driver mutations in a substantial portion of aldosterone-producing adenomas, including the genes KCNJ5 (encoding inwardly rectifying potassium channel GIRK4), CACNA1D (encoding a subunit of L-type voltage-gated calcium channel Ca_V1.3), ATP1A1 (encoding a subunit of Na⁺/K⁺-ATPase), ATP2B3 (encoding a Ca²⁺-ATPase), and CTNNB1 (encoding ß-catenin). In addition, aldosterone-producing cells were recently reported to form small clusters (aldosterone-producing cell clusters) beneath the adrenal capsule. Such clusters accumulate with age and appear to be more frequent in individuals with idiopathic hyperaldosteronism. The fact that they are associated with somatic mutations implicated in aldosterone-producing adenomas also suggests a precursor function for adenomas. Rare germline variants of CYP11B2 (encoding aldosterone synthase), CLCN2 (encoding voltage-gated chloride channel ClC-2), KCNJ5, CACNA1H (encoding a subunit of T-type voltage-gated calcium channel Ca_V3.2), and CACNA1D have been reported in different subtypes of familial hyperaldosteronism. Collectively, these studies suggest that primary aldosteronism is largely due to genetic mutations in single genes, with potential implications for diagnosis and therapy.

Plasma Aldosterone After Seated Saline Infusion Test Outperforms Captopril Test at Predicting Clinical Outcomes After Adrenalectomy for Primary Aldosteronism

OBJECTIVE

The saline infusion test (SIT) and the captopril test (CT) are widely used as confirmatory tests for primary aldosteronism (PA). We hypothesized that post-SIT and post-CT plasma aldosterone concentrations (PAC) indicate the severity of aldosterone-producing adenoma (APA) and might predict clinical outcome.

METHODS

We recruited 216 patients with APA in the Taiwan Primary Aldosteronism Investigation (TAIPAI) registry who received both seated SIT and CT as confirmatory tests. The data of 143 patients who underwent adrenalectomy with complete follow-up after diagnosis were included in the final analysis. We determined the proportion of patients achieving clinical success in accordance with the Primary Aldosteronism Surgical Outcome consensus. Logistic regression analysis was conducted to identify preoperative factors associated with cure of hypertension.

RESULTS

Complete clinical success was achieved in 48 (33.6%) patients and partial clinical success in 59 (41.2%) patients; absent clinical success was seen in 36 (25.2%) of 143 patients. Post-SIT PAC but not post-CT PAC was independently associated with clinical outcome. Higher levels of post-SIT PAC had a higher likelihood of clinical benefit (complete plus partial clinical success; odds ratio = 1.04 per ng/dl increase, 95% confidence interval = 1.01, 1.06; P = 0.004). Patients with post-SIT PAC > 25 ng/dl were more likely to have a favorable clinical outcome after adrenalectomy. This cutoff value translated into a positive predictive value of 86.0%.

CONCLUSIONS

We suggest that post-SIT PAC is a better predictor than post-CT PAC for clinical success in PA post adrenalectomy.

Adrenalectomy Improves the Long-Term Risk of End-Stage Renal Disease and Mortality of Primary Aldosteronism

OBJECTIVE

Primary aldosteronism (PA) is a common cause of secondary hypertension, and the long-term effect of excess aldosterone on kidney function is unknown.

PATIENTS AND METHODS

We used a longitudinal population database from the Taiwan National Health Insurance system and applied a validated algorithm to identify patients with PA diagnosed between 1997 and 2009.

RESULTS

There were 2699 patients with PA recruited, of whom 761 patients with an aldosterone-producing adenoma (APA) were identified. The incidence rate of end-stage renal disease (ESRD) was 3% in patients with PA after targeted treatments and 5.2 years of follow-up, which was comparable to the rate in controls with essential hypertension (EH). However, after taking mortality as a competing risk, we found a significantly lower incidence of ESRD when comparing patients with PA vs EH [subdistribution hazard ratio (sHR), 0.38; P = 0.007] and patients with APA vs EH (sHR 0.55; P = 0.021) after adrenalectomy; however, we did not see similar results in groups with mineralocorticoid receptor antagonist (MRA)‒treated PA vs EH. There was also a significantly lower incidence of mortality in groups with PA and APA who underwent adrenalectomy than among EH controls (P < 0.001).

CONCLUSION

Regarding incident ESRD, patients with PA were comparable to their EH counterparts after treatment. After adrenalectomy, patients with APA had better long-term outcomes regarding progression to ESRD and mortality than hypertensive controls, but MRA treatments did not significantly affect outcome.

KCNJ5 mutation as a predictor for resolution of hypertension after surgical treatment of aldosterone-producing adenoma

OBJECTIVE

To investigate the effect of KCNJ5 mutations on the cure of hypertension in patients with aldosterone-producing adenoma (APA) after unilateral adrenalectomy.

METHODS

Our study included 142 patients with APA, who were detected with an endocrinological abnormality and diagnosed with hypertension, as confirmed by pathological analysis. We sequenced KCNJ5, ATP1A1, ATP2B3, CACNA1D, and CTNNB1 from APA tissue samples, and performed a retrospective analysis to determine correlations between wild-type or mutated KCNJ5 and patient clinical characteristics.

RESULTS

Somatic KCNJ5 mutations were identified in 106 of 142 patients with APA, 136 of whom had resolution of hyporeninemic-hyperaldosteronemia 1 year after surgery. Of the 136 patients, 81 patients had resolution of hypertension ('Cured group' vs. 'Improved group'). We found increased prevalence of KCNJ5 mutations in the Cured group compared to the Improved group (85.2% vs. 60.0%, respectively; P = 0.002), which was associated with younger age, shorter duration of hypertension, fewer antihypertensive medications, lower BMI, higher aldosterone level, higher estimated glomerular filtration rate, and milder vascular complications. In both groups we found that harbouring a KCNJ5 mutation, taking fewer antihypertensive medications, and the duration of hypertension were independently associated with resolution of hypertension by unilateral adrenalectomy. In patients with KCNJ5-mutated APA, left ventricular hypertrophy was significantly decreased by surgical treatment in patients from either Cured or Improved groups, although those patients with wild-type KCNJ5 showed no change.

CONCLUSIONS

Testing for KCNJ5 mutations in young patients with APA may provide a prognostic indication for resolution of hypertension and severity of vascular complications.

Cellular and Genetic Causes of Idiopathic Hyperaldosteronism

Primary aldosteronism affects ≈5% to 10% of hypertensive patients and has unilateral and bilateral forms. Most unilateral primary aldosteronism is caused by computed tomography-detectable aldosterone-producing adenomas, which express CYP11B2 (aldosterone synthase) and frequently harbor somatic mutations in aldosterone-regulating genes. The cause of the most common bilateral form of primary aldosteronism, idiopathic hyperaldosteronism (IHA), is believed to be diffuse hyperplasia of aldosterone-producing cells within the adrenal cortex. Herein, a multi-institution cohort of 15 IHA adrenals was examined with CYP11B2 immunohistochemistry and next-generation sequencing. CYP11B2 immunoreactivity in adrenal glomerulosa harboring non-nodular hyperplasia was only observed in 4/15 IHA adrenals suggesting that hyperplasia of CYP11B2-expressing cells may not be the major cause of IHA. However, the adrenal cortex of all IHA adrenals harbored at least 1 CYP11B2-positive aldosterone-producing cell cluster (APCC) or micro-aldosterone-producing adenomas. The number of APCCs per case (and individual APCC area) in IHA adrenals was significantly larger than in normotensive controls. Next-generation sequencing of DNA from 99 IHA APCCs demonstrated somatic mutations in genes encoding the L-type calcium voltage-gated channel subunit α 1-D ( CACNA1D, n=57; 58%) and potassium voltage-gated channel subfamily J-5 ( KCNJ5, n=1; 1%). These data suggest that IHA may result from not only hyperplasia but also the accumulation or enlargement of computed tomography-undetectable APCC harboring somatic aldosterone-driver gene mutations. The high prevalence of mutations in the CACNA1D L-type calcium channel provides a potential actionable therapeutic target that could complement mineralocorticoid blockade and inhibit aldosterone overproduction in some IHA patients.

Timeline of Advances in Genetics of Primary Aldosteronism

The overwhelming majority of cases of primary aldosteronism (PA) occur sporadically due to a unilateral aldosterone-producing adenoma (APA) or bilateral idiopathic adrenal hyperplasia. Familial forms of PA are rare with four subtypes defined to date (familial hyperaldosteronism types I-IV). The molecular basis of familial hyperaldosteronism type I (FH type I or glucocorticoid-remediable aldosteronism) was established in 1992; two decades later the genetic variant causing FH type III was identified and germline mutations causing FH type IV and FH type II were determined soon after. Effective diagnostic protocols and methods to detect the overactive gland in unilateral PA by adrenal venous sampling followed by laparoscopic adrenalectomy have made available APAs for scientific studies. In rapid succession, following the widespread use of next-generation sequencing, recurrent somatic driver mutations in APAs were identified in genes encoding ion channels and transporters. The development of highly specific monoclonal antibodies against key enzymes in adrenal steroidogenesis has unveiled the heterogeneous features of the diseased adrenal in PA and helped reveal the high proportion of APAs with driver mutations. We discuss what is known about the genetics of PA that has led to a clearer understanding of the disease pathophysiology.

Prevalence and Histopathological Characteristics of KCNJ5 Mutant Aldosterone-Producing Adenomas in a Multi-Ethnic Malaysian Cohort

Studies on excised adrenals from primary aldosteronism patients have found that somatic mutations in KCNJ5 frequently cause excess aldosterone production in the culprit aldosterone-producing adenoma (APA). KCNJ5 mutant APAs were reported to be peculiarly overrepresented among young females and in Oriental cohorts, compared to their older male, or Caucasian counterparts. These larger APAs were also reported to have similarities with the zona fasciculata (ZF) in the adrenal both from the steroid production profile and the morphology of the cell. We therefore aimed to corroborate these findings by characterizing the APAs from a multi-ethnic Malaysian cohort. The prevalence of KCNJ5 mutations was estimated through targeted DNA sequencing of KCNJ5 in 54 APAs. Confirmation of APA sample acquisition was performed by CYP11B2 immunohistochemistry (IHC) staining. The ZF steroid production profile was based on the ZF enzyme CYP17A1 IHC staining, and ZF cell morphology was based on a high cytoplasm to nucleus ratio. Seventeen (31.5%) APAs studied, harbored a KCNJ5 mutation. No female over-representation was seen in this cohort though females were found to have a higher expression of CYP11B2 than males (p = 0.009; Mann-Whitney U test). Age at adrenalectomy correlated negatively with the percentage of ZF-like cells in the APA (p = 0.01; Spearman's rho) but not with the KCNJ5 genotype. KCNJ5 mutant APAs had a high percentage of ZF-like cells (and high CYP17A1 expression) but so did the wild-type APAs. In summary, prevalence of KCNJ5 mutant APAs in this cohort was similar to other Caucasian cohorts, however, over-representation of females did not occur, which is similar to some studies in Oriental cohorts.

The Expanding Spectrum of Primary Aldosteronism: Implications for Diagnosis, Pathogenesis, and Treatment

Primary aldosteronism is characterized by aldosterone secretion that is independent of renin and angiotensin II and sodium status. The deleterious effects of primary aldosteronism are mediated by excessive activation of the mineralocorticoid receptor that results in the well-known consequences of volume expansion, hypertension, hypokalemia, and metabolic alkalosis, but it also increases the risk for cardiovascular and kidney disease, as well as death. For decades, the approaches to defining, diagnosing, and treating primary aldosteronism have been relatively constant and generally focused on detecting and treating the more severe presentations of the disease. However, emerging evidence suggests that the prevalence of primary aldosteronism is much greater than previously recognized, and that milder and nonclassical forms of renin-independent aldosterone secretion that impart heightened cardiovascular risk may be common. Public health efforts to prevent aldosterone-mediated end-organ disease will require improved capabilities to diagnose all forms of primary aldosteronism while optimizing the treatment approaches such that the excess risk for cardiovascular and kidney disease is adequately mitigated. In this review, we present a physiologic approach to considering the diagnosis, pathogenesis, and treatment of primary aldosteronism. We review evidence suggesting that primary aldosteronism manifests across a wide spectrum of severity, ranging from mild to overt, that correlates with cardiovascular risk. Furthermore, we review emerging evidence from genetic studies that begin to provide a theoretical explanation for the pathogenesis of primary aldosteronism and a link to its phenotypic severity spectrum and prevalence. Finally, we review human studies that provide insights into the optimal approach toward the treatment of primary aldosteronism.

Plasma Aldosterone Concentration as a Determinant for Statin Use among Middle-Aged Hypertensive Patients for Atherosclerotic Cardiovascular Disease

The use of statin therapy on the prevention of atherosclerotic cardiovascular disease (ASCVD) is recommended by the American College of Cardiology (ACC) and the American Heart Association (AHA); nevertheless, its validation on primary aldosteronism (PA) patients has not been reported. We investigated the risk of incident ASCVD in middle-aged patients with PA compared with essential hypertension (EH) based on ACC/AHA recommendations. We enrolled 461 PA patients and 553 EH patients. Even though the ratio of metabolic syndrome in each group was similar, the PA group had higher systolic blood pressures, higher low-density lipoprotein levels, higher plasma aldosterone concentration (PAC), lower high-density lipoprotein levels, and higher 10-year ASCVD compared to the EH group. The discriminative power for predicting ASCVD by the recommended statin use from the ACC/AHA guidelines was proper in the PA group (i.e., under the receiver operating characteristic curve (95% confidence interval; 0.94 (0.91–0.96)). The generalized additive model showed patients with PAC higher than 60 ng/dL accompanying the standard timing of the statin use suggested by the ACC/AHA. The ACC/AHA guidelines have good discriminative power in the prediction of middle-aged high-risk hypertensive patients, while PAC identifies those high-risk individuals who may benefit from early statin therapy.

Higher Screening Aldosterone to Renin Ratio in Primary Aldosteronism Patients with Diabetes Mellitus

Accumulated evidence has shown that low renin hypertension is common in patients with diabetic nephropathy. However, the performance of aldosterone to renin ratio (ARR) in primary aldosteronism (PA) patients with diabetes has not been well validated. Here, we report the performance of screening ARR in PA patients with diabetes. The study enrolled consecutive patients and they underwent ARR testing at screening. Then the diagnosis of PA was confirmed from the Taiwan Primary Aldosteronism Investigation registration dataset. Generalized additive model smoothing plot was used to validate the performance of screening ARR in PA patients with or without diabetes. During this study period, 844 PA patients were confirmed and 136 (16.0%) among them had diabetes. Other 816 patients were diagnosed with essential hypertension and used as the control group and 89 (10.9%) among them had diabetes. PA patients with diabetes were older and had a longer duration of hypertensive latency, higher systolic blood pressure and lower glomerular filtration rate than those PA patients without diabetes. The cut-off value of ARR in the generalized additive model predicting PA was 65 ng/dL per ng/mL/h in diabetic patients, while 45 ng/dL per ng/mL/h in non-diabetic patients. There was a considerable prevalence of diabetes among PA patients, which might be capable of interfering with the conventional screening test. The best cut-off value of ARR, more than 65 ng/dL per ng/mL/h in PA patients with diabetes, was higher than those without diabetes.

miRNA-203 Modulates Aldosterone Levels and Cell Proliferation by Targeting Wnt5a in Aldosterone-Producing Adenomas

CONTEXT

The aberrant expression or alternation of miRNA in the pathogenesis of aldosterone-producing adenomas (APAs) is still largely unknown.

OBJECTIVE

We investigated the role of miRNA-203 (screened from miRNA microarrays) and elucidated its effects on the Wnt/β-catenin pathway regarding aldosterone production and cell proliferation in APAs.

METHODS

miR-203 expression was upregulated or downregulated by transfecting miR-203 mimics or inhibitors into primary APA cells, the human adrenocortical cell line HAC15, and C57BL/6 mice. In vitro and biochemical data were correlated with the respective clinical parameters of APAs to evaluate their clinical importance.

RESULTS

The expression of miR-203 in human APA samples was significantly lower than that of peritumor adrenal samples. Tumoral miR-203 abundance correlated negatively with both plasma aldosterone level and tumor size in patients with APAs. miR-203 inhibitors increased aldosterone production and cell proliferation in HAC15 cells, and restoration of expression via miR-203 mimics showed decreased cell proliferation and aldosterone hypersecretion in APA cell cultures. In vivo selective inhibition of miR-203 via intra-adrenal injection of miR-203 inhibitors in mice led to a substantial increase in systolic blood pressure and plasma aldosterone levels. Additionally, the dual-luciferase reporter assay demonstrated that WNT5A is a direct target of miR-203. Furthermore, plasma Wnt5a levels in adrenal vein sampling were helpful in differentiating tumor localization, and preoperative plasma Wnt5a levels predicted the cure of hypertension after adrenalectomy.

CONCLUSION

We have demonstrated that attenuated miR-203 expression in APAs increases aldosterone production and the tumorigenesis of adrenal cells by activating the Wnt5a/β-catenin pathway.

Aldosterone Suppression by Dexamethasone in Patients With KCNJ5-Mutated Aldosterone-Producing Adenoma

CONTEXT

Aldosterone biosynthesis is regulated principally by ACTH and gene mutations as well as by angiotensin II and serum potassium. In addition, previous studies have reported the potential effects of KCNJ5 mutations in aldosterone-producing adenoma (APA) on cardiovascular diseases. However, responsiveness to ACTH in APAs according to potassium inwardly rectifying channel, subfamily J, member 5 (KCNJ5) mutations remains unknown.

OBJECTIVE

To investigate KCNJ5 genotype-specific differences in aldosterone biosynthesis in response to ACTH stimulation.

DESIGN AND SETTING

A cross-sectional study through retrieval of clinical records.

PARTICIPANTS

One hundred forty-one patients aged ≥20 years with APA were examined.

MAIN OUTCOME MEASURES

Associations between KCNJ5 mutations and clinical parameters reflecting the renin-angiotensin system [saline infusion test (SIT)] and ACTH pathways [dexamethasone suppression test (DST)].

RESULTS

KCNJ5 mutations were detected in 107 cases. In the crude comparison, patients with mutations in KCNJ5 had higher plasma aldosterone concentrations (PACs) both at baseline and after the SIT. PAC after the DST showed a significant inverse association with KCNJ5 genotypes after controlling for age, sex, tumor size, and PAC after the SIT. Immunohistochemical analysis of 101 cases revealed more abundant immunoreactivity of CYP11B1 and CYP17 in the KCNJ5-mutated group than in the KCNJ5 wild-type group.

CONCLUSION

This report of marked suppression of PAC by dexamethasone in patients with KCNJ5-mutated APAs indicates that such APAs respond to endogenous ACTH more readily than APAs in nonmutated cases. Further molecular and epidemiologic studies are required to validate our results and clarify the clinical effectiveness of the DST for predicting KCNJ5 mutations before adrenalectomy.

Prevalence of Somatic KCNJ5 Mutations in Thai Patients With Aldosterone-Producing Adrenal Adenomas

Somatic KCNJ5 mutations result in excess aldosterone production and are reported to be more common in Asia than elsewhere. To assess the prevalence of somatic KCNJ5 mutations in Thai patients with aldosterone-producing adrenal adenomas (APAs) in a single tertiary center, we analyzed the paraffin-embedded tissue of KCNJ5 mutations from 96 patients with sporadic APAs who underwent unilateral laparoscopic adrenalectomy at our center during 2007 to 2016. We also assessed the clinical characteristics, treatment outcomes, and biochemistry and histologic differences among patients with and without somatic KCNJ5 mutations. Of the 96 patients with APA, 67 (70%) had somatic mutations of the KCNJ5 gene: 39 patients with p.G151R, 26 patients with p.L168R, one patient with p.T158A, and one patient with p.W126R. All patients presented with hypertension. Hypokalemia was documented in 98% of patients. The hypertension cure rate at 1 year after surgery was 35%. Patients with somatic KCNJ5 mutations required more potassium supplementation and had adrenal histology compatible with zona fasciculata–like cells compared with patients without the mutations (all P < 0.05). There were no significant differences in preoperative plasma aldosterone concentration (PAC), plasma renin activity, aldosterone/renin ratio, potassium level, treatment of hypertension, tumor size, and hypertension cure rate among patients in the KCNJ5-mutant and nonmutant groups. In a multivariate analysis, a higher PAC was associated with the presence of somatic KCNJ5 mutations. In summary, the prevalence of somatic KCNJ5 mutations in patients with sporadic APAs in Thailand, an Asian country with residents of different ethnic backgrounds, is comparable to previous reports in Asia.

Surgical outcomes of patients with primary aldosteronism lateralized with I-131-6 β-iodomethyl-norcholesterol single photon emission/computed tomography without discontinuation or modification of antihypertensive medications

Objectives

Adrenocortical scintigraphy for patients with primary aldosteronism (PA) without discontinuation or modification of antihypertensive medications is of concern because of drug interference with the renin-angiotensin-aldosterone system. We report the surgical outcomes of patients with PA lateralized with adrenocortical scintigraphy without drug discontinuation or modification.

Materials and Methods

We retrospectively reviewed 34 patients with PA with computed tomography (CT)-documented adrenal tumors who had undergoing subsequent I-131-6 β-iodomethyl-norcholesterol (NP-59) single photon emission CT (SPECT)/CT followed by unilateral adrenalectomy according to the results of NP-59 uptake between May 2005 and December 2014. All enrolled patients underwent standard confirmatory tests and lateralization with NP-59 SPECT/CT without discontinuation of existing antihypertensive medications, including spironolactone. The pathological findings, hypertension outcomes, and biochemical changes were reported. The accuracy of NP-59 SPECT/CT without drug discontinuation or modification was also evaluated.

Results

None of the 34 enrolled patients (M:F = 16:18) had complications such as a hypertensive crisis, life-threatening hypokalemic event, or cardiac arrhythmia. Pathology disclosed 31 (91%) adenomas and three cases of hyperplasia. Hypertension cure and improvement were observed in 12 (35%) and 18 (53%) patients, respectively. All of the 30 patients (100%) without postoperative use of beta-blockers and with an available postoperative aldosterone/renin ratio achieved a biochemical cure. The positive predictive values of NP-59 SPECT/CT were 91%, 88%, and 100% for the pathological findings, hypertension outcomes, and biochemical changes, respectively.

Conclusion

Noninvasive NP-59 SPECT/CT without discontinuation or modification of antihypertensive medications not only provided accurate lateralization and safety but also resulted in a high improvement rate for PA-associated hypertension.