Adrenal histopathology in primary aldosteronism: is it time for a change?

The predictors of long-term outcomes after targeted therapy for primary Aldosteronism

Unilateral primary aldosteronism is thought to be a surgically curable disease, and unilateral adrenalectomy is the mainstay treatment. The Primary Aldosteronism Surgical Outcome (PASO) consensus was developed to assess clinical and biochemical outcomes to standardize the classification of surgical outcomes. However, fewer than half of patients are cured of hypertension after adrenalectomy; therefore, preoperative patient counseling and evaluation might be necessary. Moreover, current studies show that genetic mutations and histopathology classification are associated with the treatment outcome. The Task Force of Taiwan PA recommends using a specific scoring system, including the PASO score and nomogram-based preoperative score, to predict the clinical outcome before adrenalectomy. Herein, we discuss the associations of current histopathological classification and specific somatic gene mutations with clinical outcomes after surgery.

Bilateral Nephrectomy for Resistant Hypertension and Secondary Aldosteronism in a Hemodialysis Patient: A Case Report

A 42-year-old Japanese woman with end-stage renal failure due to hypertension presented with a systolic blood pressure of 160-200 mmHg despite treatment with 4 different antihypertensive agents. The plasma aldosterone concentration (PAC) and plasma renin activity (PRA) were elevated. Adrenal vein sampling suggested bilateral excessive aldosterone secretion, whereas adrenocortical scintigraphy showed right-dominant accumulation. Open bilateral nephrectomy and right adrenalectomy improved the systolic blood pressure, PAC, and PRA. A pathological examination revealed zona glomerulosa hyperplasia but not microaldosteronoma. This report shows that bilateral nephrectomy, not unilateral adrenalectomy, is a potentially effective treatment option for resistant hypertension with an elevated renin-angiotensin-aldosterone system in hemodialysis patients.

Management and Outcomes of Primary Aldosteronism in Pregnancy: A Systematic Review

Primary aldosteronism (PA) in pregnancy (PAP) can be a serious condition and is challenging to diagnose. This study was conceived to help in the diagnosis of PAP and provide suggestions on management of PAP based on evidence retrieved using a Population, Intervention, Comparison, and Outcome search strategy. Based on the changes of aldosterone and renin occurring in normal pregnancies, we developed a nomogram that will allow to identify PAP cases. Moreover, we found that published PAP cases fell into 4 main groups differing for management and outcomes: (1) unilateral medically treated, (2) unilateral surgically treated, (3) bilateral medically treated and (4) familial forms. Results showed that complications involved 62.2% of pregnant women with nonfamilial PA and 18.5% of those with familial hyperaldosteronism type I. Adrenalectomy during pregnancy in women with PAP did not improve maternal and fetal outcomes, over medical treatment alone. Moreover, cure of maternal hypertension and mother and baby outcome were better when unilateral PA was discovered and surgically treated before or after pregnancy. Therefore, fertile women with arterial hypertension should be screened for PA before pregnancy and, if necessary, subtyped to identify unilateral forms of PA. This will allow to furnish adequate counseling, a chance for surgical cure and, therefore, for a pregnancy not complicated by aldosterone excess.

Radiomics utilization to differentiate nonfunctional adenoma in essential hypertension and functional adenoma in primary aldosteronism

We performed the present study to investigate the role of computed tomography (CT) radiomics in differentiating nonfunctional adenoma and aldosterone-producing adenoma (APA) and outcome prediction in patients with clinically suspected primary aldosteronism (PA). This study included 60 patients diagnosed with essential hypertension (EH) with nonfunctional adenoma on CT and 91 patients with unilateral surgically proven APA. Each whole nodule on unenhanced and venous phase CT images was segmented manually and randomly split into training and test sets at a ratio of 8:2. Radiomic models for nodule discrimination and outcome prediction of APA after adrenalectomy were established separately using the training set by least absolute shrinkage and selection operator (LASSO) logistic regression, and the performance was evaluated on test sets. The model can differentiate adrenal nodules in EH and PA with a sensitivity, specificity, and accuracy of 83.3%, 78.9% and 80.6% (AUC = 0.91 [0.72, 0.97]) in unenhanced CT and 81.2%, 100% and 87.5% (AUC = 0.98 [0.77, 1.00]) in venous phase CT, respectively. In the outcome after adrenalectomy, the models showed a favorable ability to predict biochemical success (Unenhanced/venous CT: AUC = 0.67 [0.52, 0.79]/0.62 [0.46, 0.76]) and clinical success (Unenhanced/venous CT: AUC = 0.59 [0.47, 0.70]/0.64 [0.51, 0.74]). The results showed that CT-based radiomic models hold promise to discriminate APA and nonfunctional adenoma when an adrenal incidentaloma was detected on CT images of hypertensive patients in clinical practice, while the role of radiomic analysis in outcome prediction after adrenalectomy needs further investigation.

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

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

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

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

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

Recent Development toward the Next Clinical Practice of Primary Aldosteronism: A Literature Review

For the last seven decades, primary aldosteronism (PA) has been gradually recognized as a leading cause of secondary hypertension harboring increased risks of cardiovascular incidents compared to essential hypertension. Clinically, PA consists of two major subtypes, surgically curable and uncurable phenotypes, determined as unilateral or bilateral PA by adrenal venous sampling. In order to further optimize the treatment, surgery or medications, diagnostic procedures from screening to subtype differentiation is indispensable, while in the general clinical practice, the work-up rate is extremely low even in the patients with refractory hypertension because of the time-consuming and labor-intensive nature of the procedures. Therefore, a novel tool to simplify the diagnostic flow has been recently in enormous demand. In this review, we focus on recent progress in the following clinically important topics of PA: prevalence of PA and its subtypes, newly revealed histopathological classification of aldosterone-producing lesions, novel diagnostic biomarkers and prediction scores. More effective strategy to diagnose PA based on better understanding of its epidemiology and pathology should lead to early detection of PA and could decrease the cardiovascular and renal complications of the patients.

The Genotype-Based Morphology of Aldosterone-Producing Adrenocortical Disorders and Their Association with Aging

Primary aldosteronism (PA) is the most common cause of secondary hypertension, and is associated with an increased incidence of cardiovascular events. PA itself is clinically classified into the following two types: unilateral PA, mostly composed of aldosteroneproducing adenoma (APA); and bilateral hyperaldosteronism, consisting of multiple aldosterone-producing micronodules (APMs) and aldosterone-producing diffuse hyperplasia. Histopathologically, those disorders above are all composed of compact and clear cells. The cellular morphology in the above-mentioned aldosterone-producing disorders has been recently reported to be closely correlated with patterns of somatic mutations of ion channels including KCNJ5, CACNA1D, ATP1A1, ATP2B3, and others. In addition, in non-pathological adrenal glands, APMs are frequently detected regardless of the status of the renin-angiotensin-aldosterone system (RAAS). Aldosterone-producing nodules have been also proposed as non-neoplastic nodules that can be identified by hematoxylin and eosin staining. These non-neoplastic CYP11B2-positive nodules could represent possible precursors of APAs possibly due to the presence of somatic mutations. On the other hand, aging itself also plays a pivotal role in the development of aldosterone-producing lesions. For instance, the number of APMs was also reported to increase with aging. Therefore, recent studies indicated the novel classification of PA into normotensive PA (RAAS-independent APM) and clinically overt PA.

Cortisol Co-Secretion and Clinical Usefulness of ACTH Stimulation Test in Primary Aldosteronism: A Systematic Review and Biases in Epidemiological Studies

The hypothalamus-pituitary-adrenal (HPA) axis plays an important role in primary aldosteronism. Aldosterone biosynthesis is regulated not only by angiotensin II in the renin-angiotensin-aldosterone system, but also by adrenocorticotropic hormone (ACTH), one of the key components of the HPA axis. Although previous studies have reported cortisol cosecretion in primary aldosteronism, particularly aldosterone-producing adenoma (APA), the clinical relevance of such aldosterone and cortisol cosecretion from APA and hypertension or other metabolic disorders has not been fully established. Several somatic mutations including KCNJ5 and CACNA1D are known to induce autonomous production of aldosterone in APA, and the aldosterone responsiveness to ACTH may vary according to each mutation. The ACTH stimulation test has been reported to be a useful tool to distinguish the subtypes of primary aldosteronism (e.g., unilateral vs bilateral) in some studies, but it has not been commonly applied in clinical practice due to limited evidence. Given the recent advancement of imaging, omics research, and computational approach, it is important to summarize the most updated evidence to disentangle the potential impact of cortisol excess in primary aldosteronism and whether the ACTH stimulation test needs to be considered during the diagnostic process of primary aldosteronism. In this article, we conducted a systematic review of epidemiological studies about (i) cortisol cosecretion in primary aldosteronism and (ii) the ACTH stimulation test for the diagnosis of primary aldosteronism (including subtype diagnosis). Then, we discussed potential biases (e.g., confounding bias, overadjustment, information bias, selection bias, and sampling bias) in the previous studies and introduced some advanced epidemiological/statistical methods to minimize these limitations. A better understanding of biases and epidemiological perspective on this topic would allow us to produce further robust evidence and balanced discussion about the causal mechanisms involving the HPA axis and clinical usefulness of the ACTH stimulation test among patients with primary aldosteronism.

Resolution of drug-resistant hypertension by adrenal vein sampling-guided adrenalectomy: a proof-of-concept study

Drug-resistant hypertension (RH) is a very high-risk condition involving many hypertensive patients, in whom primary aldosteronism (PA) is commonly overlooked. Hence, we aimed at determining if (1) adrenal vein sampling (AVS) can identify PA in RH patients, who are challenging because of receiving multiple interfering drugs; (2) AVS-guided adrenalectomy can resolve high blood pressure (BP) resistance to treatment in these patients.

Based on a pilot study we selected from 1016 consecutive patients referred to our Centre for ‘difficult-to-treat’ hypertension those with RH, for an observational prospective cohort study. We excluded those non-adherent to treatment (by therapeutic drug monitoring) and those with pseudo-RH (by 24-h BP monitoring), which left 110 patients who met the European Society of Cardiology/European Society of Hypertension (ESC/ESH) 2013 definition for RH. Of these patients, 77 were submitted to AVS, who showed unilateral PA in 27 (mean age 55 years; male/female 19/8). Therefore, these patients underwent AVS-guided laparoscopic unilateral adrenalectomy, which resolved RH in all: 20% were clinically cured in that they no longer needed any antihypertensive treatment; 96% were biochemically cured. Systolic and diastolic BP fell from 165/100 ± 26/14 mmHg at baseline, to 132/84 ± 14/9 mmHg at 6 months after surgery (P<10−4 for both) notwithstanding the fall of number and defined daily dose (DDD) of antihypertensive drugs required to achieve BP control (P<10−4 for both). A prominent regression of cardiac and renal damage was also observed.

Thus, the present study shows the feasibility of identifying PA by AVS in RH patients, and of resolving high BP resistance to treatment in these patients by AVS-guided adrenalectomy.

Effects of Mineralocorticoid and AT1 Receptor Antagonism on The Aldosterone-Renin Ratio In Primary Aldosteronism-the EMIRA Study

CONTEXT

While current guidelines recommend the withdrawal of mineralocorticoid receptor antagonist (MRA) and renin-angiotensin system blockers for the screening and detection of primary aldosteronism (PA), this can worsen hypokalemia and control of high blood pressure (BP) values.

OBJECTIVE

To investigate whether aldosterone/renin ratio (ARR) values were affected by the MRA canrenone and/or by canrenone plus olmesartan treatment in patients with PA.

DESIGN

Within-patient study.

SETTING

The European Society of Hypertension center of excellence at the University of Padua.

PATIENTS

Consecutive patients with an unambiguous diagnosis of PA subtyped by adrenal vein sampling.

INTERVENTIONS

Patients were treated for 1 month with canrenone (50-100 mg orally), and for an additional month with canrenone plus olmesartan (10-20 mg orally). Canrenone and olmesartan were up-titrated over the first 2 weeks until BP values and hypokalemia were controlled. Patients with unilateral PA were adrenalectomized; those with bilateral PA were treated medically.

MAIN OUTCOME MEASURES

BP, plasma levels of sodium and potassium, renin and aldosterone.

RESULTS

Canrenone neither lowered plasma aldosterone nor increased renin; thus, the high ARR and true positive rate remained unaffected. Addition of the angiotensin type 1 receptor blocker raised renin and slightly lowered aldosterone, which reduced the ARR and increased the false negative rate.

CONCLUSIONS

At doses that effectively controlled serum potassium and BP values, canrenone did not preclude an accurate diagnosis in patients with PA. Addition of the angiotensin type 1 receptor blocker olmesartan slightly raised the false negative rate. Hence, MRA did not seem to endanger the accuracy of the diagnosis of PA.

10 good reasons why adrenal vein sampling is the preferred method for referring primary aldosteronism patients for adrenalectomy

: Nowadays most patients diagnosed with surgically curable primary aldosteronism have small or micro aldosterone-producing adenoma or unilateral micronodular hyperplasia, which are undetectable with available imaging technologies. Therefore, a negative imaging test by no means excludes unilateral primary aldosteronism. Moreover, about 10% of the subjects above the age of 35 years have nonfunctioning adrenal tumors, regardless of being hypertensive or not, with a prevalence that raises with aging. Hence, the finding of an adrenal mass at imaging does not reliably detect the culprit of primary aldosteronism. On the other hand, when primary aldosteronism patients are selected for adrenalectomy on the basis of demonstration of lateralized aldosterone excess at adrenal vein sampling (AVS), close to 100% are biochemically cured from the hyperaldosteronism, about 45% are cured of arterial hypertension and an additional 52% are markedly improved in terms of blood pressure control. By contrast, patients referred for surgery based on imaging alone often fail to reach these successful outcomes, indicating that surgery was unnecessary or, even worse, performed on the wrong side. For these reasons, and because of the lack of accurate and widely available alternative methods, all current guidelines recommend that AVS be offered to all primary aldosteronism patients with only few exceptions, mainly in patients unable or unwilling to undergo surgery and those with germ-line mutations causing familial primary aldosteronism. The main argument against systematic use of AVS entails its suboptimal performance, partly justified by its intrinsic technical difficulty, and its limited availability. This led to propose skipping AVS strategies for predicting surgically curable primary aldosteronism, but success has been inconsistent. The most urgent standing issue is, therefore, not to find loopholes to avoid AVS, but rather to improve its use, which means improving the rate of AVS success, through formal training of interventionists, selection of appropriate cutoffs and exploitation of a standardized procedure.

Using microwave thermal ablation to develop a subtotal, cortical-sparing approach to the management of primary aldosteronism

Objective: To investigate the feasibility and efficacy of localized, subtotal, cortical-sparing microwave thermal ablation (MTA) as a potential curative management for primary aldosteronism. The study investigated with equal importance the selected ablation of small volumes of adrenal cortex while sparing adjacent cortex. Method: An in-vivo study was carried out in swine (n = 8) where MTA was applied under direct visualization, to the adrenal glands at 45 W or 70 W for 60 s, using a lateral, side-firing probe and a non-penetrative approach. Animals were survived for 48 h post-procedurally. Animals were investigated for markers of histological, immunohistochemical and biochemical evidence of adrenal function and adrenal damage by assessing samples drawn intra-operatively and at the time of euthanasia. Results: Selected MTA (70 W for 60 s) successfully ablated small adrenocortical volumes (∼0.8 cm³) characterized by coagulative necrosis and abnormal expression of functional markers (CYP11B1 and CYP17). Non-ablated, adjacent cortex was not affected and preserved normal expression of functional markers, without increased expression of markers of heat damage (HSP-70 and HMGB-1). Limited adrenal medullary damage was demonstrated histologically, clinically and biochemically. Conclusion: MTA offers potential as an efficient methodology for delivering targeted subtotal cortical-sparing adrenal ablation. Image-guided targeted MTA may also represent a safe future modality for curative management of PA, in the setting of both unilateral and bilateral disease.

Role of estrogen receptors in modulating aldosterone biosynthesis and blood pressure

Blood pressure is lower in premenopausal women than in age-matched men; after menopause blood pressure values and the prevalence of hypertension show opposite trends indicating that estrogens contribute to maintaining normal blood pressure values in women. In experimental studies menopause increases aldosterone levels, an effect alleviated by estrogen treatment. We have recently discovered a role of estrogen receptors (ER) in controlling aldosterone biosynthesis in the human adrenocortical zona glomerulosa, which expresses both the classical ERα and β receptors and G protein-coupled estrogen receptor (GPER). We have also identified that GPER mediates an aldosterone-induced aldosterone response. We found that 17 β-estradiol exerts a dual effect: it blunts aldosterone production via ERβ, but displays a potent aldosterone secretagogue effect via GPER activation after ERβ blockade. Thus, in premenopausal women high estrogen levels might tonically blunt aldosterone synthesis via ERβ, thereby maintaining normal blood pressure; after menopause loss of this estrogen-mediated inhibition can contribute to increasing blood pressure via GPER-mediated aldosterone release. The additional findings that GPER mediates an aldosterone-induced stimulation of aldosterone biosynthesis and that GPER predominates in aldosterone-producing adenomas strongly involves this receptor in the pathophysiology of primary aldosteronism. Our purpose here was to provide an update on estrogen receptor function in the normal adrenal cortex and its relevance for the sex differences in blood pressure in light of the newly discovered role of GPER in regulating aldosterone synthesis. The implications of the novel knowledge for the treatment of estrogen-dependent malignancies with ER modulators are also discussed.

Aldosterone Stimulates Its Biosynthesis Via a Novel GPER-Mediated Mechanism

CONTEXT

The G protein-coupled estrogen receptor (GPER) mediates an aldosterone secretagogue effect of 17β-estradiol in human HAC15 adrenocortical cells after estrogen receptor β blockade. Because GPER mediates mineralocorticoid receptor-independent aldosterone effects in other cell types, we hypothesized that aldosterone could modulate its own synthesis via GPER activation.

METHODS

HAC15 cells were exposed to aldosterone in the presence or absence of canrenone, a mineralocorticoid receptor antagonist, and/or of the selective GPER antagonist G36. Aldosterone synthase (CYP11B2) mRNA and protein levels changes were the study end points. Similar experiments were repeated in strips obtained ex vivo from aldosterone-producing adenoma (APA) and in GPER-silenced HAC15 cells.

RESULTS

Aldosterone markedly increased CYP11B2 mRNA and protein expression (vs untreated samples, P < 0.001) in both models by acting via GPER, because these effects were abolished by G36 (P < 0.01) and not by canrenone. GPER-silencing (P < 0.01) abolished the aldosterone-induced increase of CYP11B2, thus proving that aldosterone acts via GPER to augment the step-limiting mitochondrial enzyme (CYP11B2) of its synthesis. Angiotensin II potentiated the GPER-mediated effect of aldosterone on CYP11B2. Coimmunoprecipitation studies provided evidence for GPER-angiotensin type-1 receptor heterodimerization.

CONCLUSION

We propose that this autocrine-paracrine mechanism could enhance aldosterone biosynthesis under conditions of immediate physiological need in which the renin-angiotensin-aldosterone system is stimulated as, for example, hypovolemia. Moreover, as APA overexpresses GPER this mechanism could contribute to the aldosterone excess that occurs in primary aldosteronism in a seemingly autonomous fashion from angiotensin II.

[Primary aldosteronism : Genetics and pathology]

BACKGROUND

Primary aldosteronism, the excessive production of the steroid hormone aldosterone, is the most common cause of secondary hypertension. Common subforms include bilateral adrenal hyperplasia and aldosterone-producing adenoma.

OBJECTIVES

The goal of this review is to summarize important publications on the genetic basis of primary aldosteronism.

RESULTS

Somatic mutations in the KCNJ5, CACNA1D, ATP1A1, and ATP2B3 genes have been described as causes of aldosterone-producing adenomas. They eventually all lead to increased cellular calcium influx and aldosterone production. The mechanisms of rare CTNNB1 mutations are less defined. Correlations between mutations and different histologic characteristics as well as gender and ethnicity remain unexplained. Recent publications suggest that bilateral hyperplasia is at least partially due to so-called aldosterone-producing cell clusters, often with mutations in CACNA1D. Rare familial forms show mutations in the CYP11B2, CLCN2, KCNJ5, CACNA1H, or CACNA1D genes.

CONCLUSIONS

These results suggest that a significant fraction of primary aldosteronism is due to somatic mutations in single genes.

The crosstalk between aldosterone and calcium metabolism in primary aldosteronism: A possible calcium metabolism-associated aberrant "neoplastic" steroidogenesis in adrenals

Intracellular calcium (Ca) levels play pivotal roles in aldosterone biosynthesis. Several somatic mutations of ion channels associated with aldosterone over-production were reported to result in over-inflow of Ca ion. Recently, the main regulators of extracellular Ca including VDR, CaSR and PTH1R were also reported to regulate steroidogenesis including aldosterone production. Therefore, not only intracellular but also extracellular Ca levels could regulate aldosterone biosynthesis. In addition, primary aldosteronism (PA) is clinically associated with not only more frequent cardiovascular events but also secondary metabolic disorders including abnormal calcium metabolism, osteoporosis and others. However, the details of Ca metabolic abnormalities associated with, including the potential correlation between those abnormalities and aldosterone overproduction, have remained virtually unknown. Therefore, in this study, we first immunolocalized Ca metabolism-related receptors (CaSR, VDR and PTH1R) in normal adrenal glands (NAs), aldosterone-producing adenomas (APAs) and cortisol-producing adenoma (CPA). We then compared the findings with clinicopathological parameters of these patients and the patterns of KCNJ5 somatic mutation of the tumors among APA patients. In vitro study was also performed to further explore the potential effects of extracellular Ca, PTH, Vitamin D and ionophore on aldosterone production. Ca metabolism-related receptors were predominantly localized in aldosterone-producing cells (ZG and APA) in both immunohistochemistry and qRT-PCR analysis. CYP11B2 mRNA was significantly increased by CaCl₂ treatment and further by adding ionophore. All the key enzymes related to aldosterone and cortisol biosynthesis including CYP11B2, CYP17A1 and CYP11B1 were upregulated by PTH treatment in this model and PTH could serve as a co-stimulator of ANG II to increase CYP11B2 expression. VDR mRNA levels were positively correlated with those of CYP11B2, CYP17A1 and CYP11B1 in APA tumor tissues and significantly higher in KCNJ5 mutated APAs than wild type. CYP11B1 levels were also significantly increased by VitD treatment. PTH1R mRNA levels were positively correlated with those of CYP17A1 and CYP11B1, both involved in cortisol production. In addition, the status of VDR was correlated with TRACP-5b levels, and that of PTH1R with serum Ca levels as well as urinary Ca excretion, respectively. Results of our present study did firstly demonstrate that aldosterone-producing cells were more sensitive to the fluctuations of extracellular Ca levels and Ca metabolism could directly influence steroidogenesis, especially "neoplastic" co-secretion of aldosterone and cortisol in APA patients.

Primary Aldosteronism: Does Underlying Pathology Impact Clinical Presentation and Outcomes Following Unilateral Adrenalectomy?

INTRODUCTION

Patients undergoing unilateral adrenalectomy for primary aldosteronism (PA) may have a solitary adenoma, unilateral hyperplasia, or multiple adenomas on final pathology. This study investigated whether the underlying pathological diagnosis was associated with differences in clinical presentation and postoperative outcomes.

METHODS

A retrospective cohort study of patients undergoing unilateral adrenalectomy for PA from 2004 to 2015 at our institution was performed. Baseline clinical and laboratory parameters, as well as postoperative biochemical and hypertension cure rates, were compared across the three aforementioned pathological groups.

RESULTS

Of 206 patients who met criteria for inclusion, 152 (73.8%) had a single adenoma, 33 (16%) had unilateral hyperplasia, and 21 (10.2%) had multiple unilateral adenomas. Patients with unilateral hyperplasia were more likely to be male (81.2% vs 57.9%, P = .03), undergo left-sided adrenalectomy (78.8% vs 47.4%, P < .01), and had a lower median adrenal venous sampling lateralization index (9.8 vs 19.8, P = .04) compared to those with solitary, but not multiple unilateral adenomas. No differences were seen in age, duration of hypertension, preoperative plasma aldosterone levels, plasma renin activities, 24-h urinary aldosterone excretion, serum potassium concentrations, and the number of preoperative antihypertensive medications across all three pathological groups. All patients achieved biochemical cure following adrenalectomy, and no significant differences in the rates of hypertension cure or improvement were observed in comparisons across pathological subtype.

CONCLUSIONS

Clinical presentation and postoperative outcomes are similar regardless of underlying pathology in patients with PA. Because one in four patients may harbor unilateral hyperplasia or multiple adenomas, total unilateral adrenalectomy should be performed as the operation of choice over adrenal-sparing approaches.

AT1AA (Angiotensin II Type-1 Receptor Autoantibodies): Cause or Consequence of Human Primary Aldosteronism?

AT1AA (Angiotensin II type-1 receptor autoantibodies) were first detected in patients with primary aldosteronism (PA) because of aldosterone-producing adenoma (APA) with an in-house developed assay, but it remained unclear if they can be ascertained also with commercially available assays and if they have a functional role. Aims of our study were to investigate if (1) commercially available kits allow detection of raised AT1AA titer in APA; (2) this titer is normalized by adrenalectomy; and (3) AT1AA display any biological roles in vitro. We measured with 2 ELISA kits the AT1AA titer in serum of APA patients and its changes after adrenalectomy. We also investigated AT1AA bioactivity by using AT1-R (angiotensin type-1 receptor)-transfected Chinese hamster ovary and human adrenocortical carcinoma cells, and by measuring aldosterone synthase (CYP11B2) expression in human adrenocortical carcinoma cells after incubation with IgG. Both kits allowed detection of higher AT1AA levels in APA patients than in healthy subjects; surgical cure of PA did not decrease this titer at 1-month follow-up. Human adrenocortical carcinoma cells stimulation with IgG purified from sera of APA patients increased both CYP11B2 expression and aldosterone release (+40% and +76%, respectively, versus healthy subjects). However, no detectable effect of IgG was seen in Chinese hamster ovary cells expressing AT1-R. These findings support the contentions that (1) the raised AT1AA titer does not seem to be a consequence of hyperaldosteronism as it did not normalize after its cure; (2) AT1AA act as weak stimulators of aldosterone biosynthesis, but this effect can be identified only by using a sensitive in vitro technique.

H-score of 11β-hydroxylase and aldosterone synthase in the histopathological diagnosis of adrenocortical tumors

PURPOSE

To assess the diagnostic performance of the H-score of 11β-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) in the histopathological diagnosis of adrenocortical tumors (ACT).

METHODS

We retrospectively evaluated 199 cases of ACT, of which 85 were diagnosed as aldosterone-producing adenoma (APA), 66 as cortisol-producing adenoma (CPA), 9 as aldosterone-cortisol co-secreting adenoma, 30 as nonhyperfunctioning adenoma, and 9 as adrenocortical carcinoma (ACC). Immunohistochemical staining was performed using anti-CYP11B1 and anti-CYP11B2 monoclonal antibodies. The staining was quantified by the McCarty's H-score system. The diagnostic performance was assessed by the receiver operating characteristic curve (ROC).

RESULTS

The H-score of CYP11B1 is highest in the CPA group and lowest in the ACC group. The H-score of CYP11B2 in the APA group is significantly higher than other ACT groups. The area under ROC (AUC) of an increased H-score of CYP11B2 (>65) for the diagnosis of APA was 0.971 (95%CI 0.937-0.990). The AUC of an increased H-score of CYP11B1 (>204) for the diagnosis of CPA was 0.725 (95%CI 0.658-0.786). The AUC of a decreased H-score of CYP11B1 (<85) for the diagnosis of ACC was 0.960 (95%CI 0.923-0.983).

CONCLUSIONS

H-score of CYP11B1 and CYP11B2 are reliable tools for the histopathological subtyping of functional benign ACT and may offer some value in the histopathological diagnosis of malignant ACT.

The Prevalence of Primary Aldosteronism and Evolving Approaches for Treatment

Over six decades since primary aldosteronism was first described, much has been learned about its prevalence and optimal treatment. Estimates of the prevalence of primary aldosteronism have increased considerably over the years, even exceeding 20% in some populations of resistant hypertension. Even in patients with normal blood pressures, the prevalence of overt primary aldosteronism and dysregulated aldosterone production may be more common than appreciated. Emerging data support the concept that primary aldosteronism may be better characterized as a continuum of renin-independent aldosterone production, whose severity influences the clinical presentation and risk for incident cardiovascular disease. Mineralocorticoid receptor antagonists and adrenalectomy are the mainstay treatments for primary aldosteronism and have long been considered equally efficacious. However, recent data suggest that while surgical adrenalectomy can effectively reduce cardiovascular risk, mineralocorticoid receptor antagonist therapy may require a physiologic approach to optimize efficacy.

Tumor Cell Subtypes Based on the Intracellular Hormonal Activity in KCNJ5-Mutated Aldosterone-Producing Adenoma

Aldosterone-producing adenomas (APAs) harbor marked intratumoral heterogeneity in terms of morphology, steroidogenesis, and genetics. However, an association of biological significance of morphologically identified tumor cell subtypes and genotypes is virtually unknown. KCNJ5 mutation is most frequently detected and generally considered a curable phenotype by adrenalectomy. Therefore, to explore the biological significance of KCNJ5 mutation in APA based on intracellular hormonal activities, 35 consecutively selected APAs (n=18; KCNJ5 mutated, n=17; wild type) were quantitatively examined in the whole tumor areas by newly developed digital image analysis incorporating their histological and ultrastructural features (14 cells from 2 KCNJ5-mutated APAs and 15 cells from 1 wild type) and CYP11B2 immunoreactivity. Results demonstrated that KCNJ5-mutated APAs had significantly lower nuclear/cytoplasm ratio and more abundant clear cells than wild type. CYP11B2 immunoreactivity was not significantly different between these genotypes, but a significant correlation was detected between the proportion of clear cells and CYP11B2 immunoreactivity in all of the APAs examined. CYP11B2 was predominantly immunolocalized in clear cells in KCNJ5-mutated APAs. Quantitative ultrastructural analysis revealed that KCNJ5-mutated APAs had significantly more abundant and smaller-sized mitochondria with well-developed cristae than wild type, whereas wild type had more abundant lipid droplets per unit area despite the small number of the cases examined. Our results did provide the novel insights into the morphological features of APA based on their biological significance. KCNJ5-mutated APAs were characterized by predominance of enlarged lipid-rich clear cells possibly resulting in increased neoplastic aldosterone biosynthesis.

Impact of immunohistochemistry on the diagnosis and management of primary aldosteronism: An important tool for improved patient follow-up

BACKGROUND AND AIMS

Primary aldosteronism is a common cause of secondary hypertension. Primary aldosteronism is caused by an aldosterone-producing adenoma or bilateral hyperplasia that in some cases is asymmetrical with one adrenal dominating aldosterone secretion. Most patients with aldosterone-producing adenoma are biochemically cured by unilateral adrenalectomy, but patients with bilateral hyperplasia have a significant risk of residual or recurrent disease. Here, immunohistochemistry of CYP11B1 and B2 was used to investigate whether these markers could aid in the diagnostic workup of primary aldosteronism patients.

MATERIALS AND METHODS

A total of 39 patients with primary aldosteronism who underwent unilateral adrenalectomy for a presumed adenoma during 2013-2016 were included. Immunohistochemistry using monoclonal antibodies identifying the enzymes CYP11B1 and B2 was part of routine histopathological workup in 6 cases; in 33 cases, it was applied retrospectively. The hyperplasia diagnosis was suggested when there was no dominating nodule but immunoreactivity for CYP11B2 was seen in several nodules, which were also seen on routine sections. To distinguish between adenoma and hyperplasia, a ratio between the largest and second largest CYP11B2-positive nodules was calculated.

RESULTS

In all, 22 patients had an aldosterone-producing adenoma, while 13 patients were judged to have hyperplasia. In four cases, a final diagnosis could not be established, thus these were judged equivocal. Among the 33 cases investigated retrospectively, the primary histopathological diagnosis was altered from hyperplasia to aldosterone-producing adenoma in 9 cases (27%) after immunohistochemistry, and the immunohistochemically rectified adenoma group displayed improved clinical cure rates compared to the routine H&E-diagnosed cohort. Moreover, the B2 ratio was significantly higher in adenoma than in hyperplasia and equivocal cases.

CONCLUSION

Immunohistochemistry detecting CYP11B1 and B2 expression is of great help in establishing a final histopathological diagnosis in patients with primary aldosteronism. This procedure should be part of the histopathological routine in all operated primary aldosteronism patients.

The Biology of Normal Zona Glomerulosa and Aldosterone-Producing Adenoma: Pathological Implications

The identification of several germline and somatic ion channel mutations in aldosterone-producing adenomas (APAs) and detection of cell clusters that can be responsible for excess aldosterone production, as well as the isolation of autoantibodies activating the angiotensin II type 1 receptor, have rapidly advanced the understanding of the biology of primary aldosteronism (PA), particularly that of APA. Hence, the main purpose of this review is to discuss how discoveries of the last decade could affect histopathology analysis and clinical practice. The structural remodeling through development and aging of the human adrenal cortex, particularly of the zona glomerulosa, and the complex regulation of aldosterone, with emphasis on the concepts of zonation and channelopathies, will be addressed. Finally, the diagnostic workup for PA and its subtyping to optimize treatment are reviewed.

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.

Primary aldosteronism with nonlocalizing imaging

BACKGROUND

Unilateral primary aldosteronism is surgically curable. The goal of this study was to examine outcomes based on preoperative imaging findings.

METHODS

We performed a retrospective analysis of patients with primary aldosteronism who underwent adrenal vein sampling. Patients were classified by imaging as localized (unilateral adrenal mass) or nonlocalized (no mass/bilateral masses). Outcomes were assessed as complete, partial, or absent clinical success.

RESULTS

Of 446 patients, 74.9% were localized. There were no significant demographic or biochemical differences between groups; however the imaged tumor size was larger (median 1.3 vs 1.2 cm, P = .038), and rates of lateralizing adrenal vein sampling were higher (79.0% vs 62.2%, P < .001) in the localized group. Of 289 patients who underwent adrenalectomy, adenoma was the most common finding in both groups (79.7% vs 80.3% respectively, P = .447), but median tumor size was larger in localized patients (1.5 vs 1.0 cm, P < .001). Equivalent rates of partial (94.6% vs 91.7%, P = .456) and complete (8.7% vs 9.8%, P = .801) clinical success were observed. At long-term follow-up, nonlocalized patients experienced partial reversal of clinical improvement.

CONCLUSION

Primary aldosteronism patients with nonlocalizing imaging but lateralizing adrenal vein sampling benefit from adrenalectomy. Regardless of imaging findings, adrenal vein sampling is indicated to determine whether patients may be surgically curable.

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.

Subtyping of primary aldosteronism with adrenal vein sampling: Hormone- and side-specific effects of cosyntropin and metoclopramide

BACKGROUND

Cosyntropin and metoclopramide can affect the subtyping of primary aldosteronism when used with adrenal vein sampling by exerting hormone- and side-specific effects on cortisol and aldosterone secretion. We investigated how these stimuli affect the selectivity index, the relative aldosterone secretion index, and the lateralization index in consecutive primary aldosteronism patients submitted to adrenal vein sampling.

METHODS

We recruited 171 patients; of these, 149 underwent adrenal vein sampling before and after stimulation with cosyntropin (250 µg intravenous bolus, n= 53, 73% with an aldosterone-producing adenoma) or with metoclopramide (10 mg intravenous bolus, n= 96, 65% aldosterone-producing adenoma), and 32 with an aldosterone-producing adenoma were investigated for the relative gene expression of dopamine, melanocortin 2, and 5-hydroxytryptamine (serotonin) 4 receptor with microarrays. Cosyntropin increased the selectivity index similarly on both sides; metoclopramide did not. Cosyntropin decreased relative aldosterone secretion index on the aldosterone-producing adenoma side but not contralaterally. Metoclopramide did not affect the selectivity index, but increased the relative aldosterone secretion index similarly on both sides. Because of these changes, cosyntropin decreased the lateralization index, while metoclopramide did not affect it. The relative gene expression of melanocortin 2, albeit heterogeneous across tumors, was 35% less (P<.0001) in aldosterone-producing adenoma than in the normal adrenal cortex, while dopamine receptor D2 and 5-hydroxytryptamine (serotonin) 4 receptors did not differ between tissues.

CONCLUSION

Cosyntropin, while facilitating ascertainment of selectivity, lessens the lateralization, likely because of a blunted melanocortin 2 expression in aldosterone-producing adenoma. The similar expression of dopamine and 5-hydroxytryptamine (serotonin) 4 receptors in aldosterone-producing adenoma and the normal adrenal cortex can explain why metoclopramide increased the relative aldosterone secretion index on both sides and, therefore, failed to increase the lateralization index.

Genetic screening in arterial hypertension

Studies involving adoptive families and twins have demonstrated the genetic basis of hypertension and shown that genetic factors account for about 40% of the variance in blood pressure among individuals. Arterial hypertension is genetically complex: multiple genes influence the blood pressure phenotype through allelic effects from single genes and gene-gene interactions. Moreover, environmental factors also modify the blood pressure phenotype. This complexity explains why the identification of the underlying genes has not been as successful in hypertension as in other diseases (such as type 1 and type 2 diabetes mellitus). The identification of the genetic determinants of hypertension has been most successful in endocrine forms of hypertension, which have well-defined phenotypes that permit a precise patient stratification into homogeneous cohorts. A promising area for the application of genetic testing to personalized medicine is the prediction of responses and adverse reactions to antihypertensive drugs. The identification of genetic markers of drug response will enable the design of randomized controlled trials in much smaller series of patients than is currently possible, decreasing the costs and times from drug design to clinical use and ultimately providing patients and doctors with a larger number of tools to combat hypertension, the most important risk factor for cardiovascular disease. This Review focuses on the rapidly developing field of genetic testing in patients with arterial hypertension.

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

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

Normoaldosteronemic aldosterone-producing adenoma: immunochemical characterization and diagnostic implications

BACKGROUND

A high aldosterone-renin ratio (ARR) is commonly used to identify primary aldosteronism, but the ARR is high when renin is low, even if plasma aldosterone concentration values are normal, suggesting the existence of 'normoaldosteronemic' primary aldosteronism. However, most such cases did not undergo adrenalectomy; moreover, because of the lack of antibody for the human CYP11B2 (aldosterone synthase), conclusive demonstration of a normoaldosteronemic aldosterone-producing adenoma was not possible thus far.

METHOD

In 2003, a lady presented with severe hypertension a right adrenal nodule, low renin, high ARR, but normal plasma aldosterone concentration. As adrenal vein sampling showed lateralized aldosterone secretion, she underwent left adrenalectomy, which consistently normalized blood pressure (BP) and renin during 11-year follow-up.

RESULT AND CONCLUSION

The development of a novel monoclonal antibody for the human CYP11B2 in 2014 allowed immunochemically identification of a CYP11B2-positive adenoma in the resected adrenal. Moreover, this case unequivocally demonstrates for the first time the existence of normoaldosteronemic aldosterone-producing adenoma, which suggests that many cases of 'low renin-essential hypertension' might instead have a surgically curable form of primary aldosteronism.

Primary Aldosteronism: New Answers, New Questions

There have been 2, and possibly 3, major questions for primary aldosteronism (PA) answered at least in principle over the past 5 years. The first is that of somatic mutations underlying the majority of aldosterone producing adenomas. The second is the extension of our knowledge of the genetics of familial hypertension, and the third the role of renal intercalated cells in sodium homeostasis. New questions for the next 5 years include a single accepted confirmatory/exclusion test; standardisation of assays and cut-offs; alternatives to universal adrenal venous sampling; reclassification of 'low renin hypertension'; recognition of the extent of 'occult' PA; inclusion of low-dose mineralocorticoid receptor antagonist in first-line therapy for hypertension; and finally, possible resolution of the aldosterone/inappropriate sodium status enigma at the heart of the cardiovascular damage in PA.

Steroid Hormone Production in Patients with Aldosterone Producing Adenomas

Primary aldosteronism encompasses 2 major underlying causes: (1) aldosterone producing adenoma and (2) bilateral adrenal hyperplasia. In addition to the aldosterone excess, increased production of other compounds of the steroidogenic pathways may be involved. Until recently, most studies examined the production of steroids other than aldosterone in tumor tissue, urine, or peripheral plasma samples, but several new studies have also addressed steroid levels in adrenal venous blood samples using liquid chromatography tandem mass spectrometry. Plasma and tissue levels of several precursors of aldosterone with mineralocorticoid activity are higher in patients with aldosterone producing adenomas than in those with bilateral hyperplasia. These include corticosterone, deoxycorticosterone, and their 18-hydroxylated metabolites. Similarly, urinary, peripheral, and adrenal venous concentrations of the hybrid steroids 18-oxocortisol and 18-hydroxycortisol are higher in patients with aldosterone producing adenomas than in bilateral hyperplasia. Differences in the pathophysiology and in clinical and biochemical phenotypes caused by aldosterone producing adenomas and bilateral adrenal hyperplasia may be related to the differential expression of steroidogenic enzymes, and associated to specific underlying somatic mutations. Correct appreciation of differences in steroid profiling between aldosterone producing adenomas and bilateral adrenal hyperplasia may not only contribute to a better understanding of the pathogenesis of primary aldosteronism but may also be helpful for future subtyping of primary aldosteronism.