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

Context: The prevalence of unilateral primary aldosteronism (UPA) with cortisol co-secretion varies geographically. Objective: To investigate the prevalence and clinical characteristics of UPA with cortisol co-secretion in a Chinese population. Design: Retrospective cohort study. Methods: We recruited 580 patients with UPA who underwent cosyntropin stimulation test (CST) after the 1-mg dexamethasone suppression test (DST) and retrospectively analyzed the clinical characteristics and postoperative outcomes of UPA with and without cortisol co-secretion. Results: UPA with cortisol co-secretion (1 mg DST>1.8 ug/dL) was identified in 65 of 580 (11.2%) patients. These patients were characterized by older age, longer duration of hypertension, higher concentration of plasma aldosterone and midnight cortisol, lower adrenocorticotropic hormone (ACTH) and dehydroepiandrosterone sulfate (DHEAS), larger tumor diameter, and more history of diabetes mellitus. Cortisol and aldosterone levels were higher and DHEAS level was lower in UPA with cortisol co-secretion at 0-120 min after CST. Among 342 UPA patients with KCNJ5 gene sequencing and follow-up results, the complete clinical success rate was lower in UPA with cortisol co-secretion (33.3% vs. 56.4%, P<0.05); the complete biochemical success rate and KCNJ5 mutation did not differ between the two groups. Age, tumor size, and ACTH were independent predictors of UPA with cortisol co-secretion. Sex, BMI, duration of hypertension, KCNJ5 mutation, and cortisol co-secretion were independent predictors for complete clinical success in UPA after surgery. Conclusions: UPA with cortisol co-secretion is not uncommon in China, but the clinical features were distinctly different from those without co-secretion. Cortisol co-secretion is an independent risk factor for incomplete clinical success after surgery in UPA.

A comparison of the performance of 68Ga-Pentixafor PET/CT versus adrenal vein sampling for subtype diagnosis in primary aldosteronism.

Objective: To investigate the diagnostic efficiency and prognostic value of 68Ga-Pentixafor PET/CT in comparison with adrenal vein sampling (AVS) for functional lateralization in primary aldosteronism (PA). Histology and long-term clinical follow-up normally serve as the gold standard for such diagnosis. Methods: We prospectively recruited 26 patients diagnosed with PA. All patients underwent 68Ga-Pentixafor PET/CT and AVS. Postsurgical biochemical and clinical outcomes of patients with unilateral primary aldosteronism (UPA), as diagnosed by PET/CT or AVS, were assessed by applying standardized Primary Aldosteronism Surgical Outcome (PASO) criteria. Immunohistochemistry (IHC) was performed to detect the expression of aldosterone synthase (CYP11B2) and CXCR4. Results: On total, 19 patients were diagnosed with UPA; of these, 13 patients were lateralized by both PET/CT and AVS, four patients were lateralized by PET-only, and two by AVS-only. Seven subjects with no lateralization on AVS and PET received medical therapy. All patients achieved complete biochemical success except one with nodular hyperplasia lateralized by AVS alone. The consistency between PET/CT and AVS outcomes was 77% (20/26). Moreover, CYP11B2-positive nodules were all CXCR4-positive and showed positive findings on PET. Patients who achieved complete biochemical and clinical success had a higher uptake on PET as well as stronger expression levels of CXCR4 and CYP11B2. Conclusion: Our analysis showed that 68Ga-Pentixafor PET/CT could enable non-invasive diagnosis in most patients with PA and identify additional cases of unilateral and surgically curable PA which could not be classified by AVS. 68Ga-Pentixafor PET/CT should be considered as a first-line test for the future classification of PA.

Subtype-specific Body Composition and Metabolic Risk in Patients With Primary Aldosteronism.

BACKGROUND: Primary aldosteronism (PA) is associated with increased metabolic risks. However, controversy exists as to which subtype of PA has a higher metabolic risk between bilateral and lateralized PA. This study aimed to assess the body composition of 2 PA subtypes, bilateral PA and lateralized PA, according to sex and autonomous cortisol secretion (ACS) and their contribution to comorbidities. DESIGN AND METHODS: A total of 400 patients with PA (females, n = 210) and 1:10 age- and sex-matched healthy controls (n = 4000) were enrolled. The skeletal muscle area (SMA), subcutaneous fat area, and visceral fat area (VFA) at the third lumbar spine were calculated using abdominal computed tomography-based body composition analysis. RESULTS: Patients with bilateral PA had higher body mass index (BMI) in both sexes (all P < .05). Hemoglobin A1c level and the prevalence of diabetes were higher in female patients with bilateral PA than in those with lateralized PA (all P < .05). The VFA/BMI ratio was significantly higher in bilateral PA patients than in lateralized PA patients (5.77 ± 2.69 vs 4.56 ± 2.35 in men; 4.03 ± 2.58 vs 2.53 ± 2.05 in women, all P < .001). PA patients with ACS showed decreased SMA compared to those without ACS. Compared with healthy controls, all patients with bilateral PA and female patients with lateralized PA showed significantly higher VFA and VFA/BMI. CONCLUSIONS: Patients with bilateral PA were more obese and had higher VFA levels than those with lateralized PA. Despite a milder form of PA, this metabolically unfavorable visceral fat distribution may lead to a higher metabolic risk in patients with bilateral PA.

Epigenetic alterations of 11beta-hydroxysteroid dehydrogenase 1 gene in the adipose tissue of patients with primary aldosteronism.

11Beta-hydroxysteroid dehydrogenase 1 (11ß-HSD1) is a key enzyme involved in metabolic syndrome. Transcript-specific epigenetic regulation of the gene encoding 11ß-HSD1 (HSD11B1) has been reported. We examined the mRNA level and methylation status of the HSD11B1 promoter region in the adipose tissue of patients with primary aldosteronism (PA). We compared 10 tissue specimens from patients with PA caused by aldosterone-producing adenoma (APA) with 8 adipose tissue specimens from patients with subclinical Cushing's syndrome (SCS) caused by cortisol-producing adenomas, 4 tissue specimens from patients with Cushing's adenoma (Cu), or 7 tissue specimens from patients with non-functioning adrenal adenoma (NFA). PA, SCS, and Cu were diagnosed according to the guideline of the Japan Endocrine Society. The mRNA level of HSD11B1 was quantified using real-time PCR. Isolated DNA was treated with bisulfite and amplified using primers specific to the human HSD11B1 promoter region. The glycohemoglobin level was significantly higher in patients with APA, SCS, or Cu than in those with NFA (p < 0.05). Blood pressure was significantly higher in patients with APA than in those with SCS, Cu, or NFA (p < 0.01). The HSD11B1 mRNA level was significantly increased in the adipose tissues of APA or SCS patients compared with Cu or NFA patients (p < 0.05). The methylation ratio was significantly lower in SCS patients than in APA, Cu, or NFA patients (p < 0.05). HSD11B1 expression is partly controlled by an epigenetic mechanism in human tissues. The pathophysiological role of epigenetic regulation of HSD11B1 expression in adipose tissue requires further study.

Urine steroid metabolomics as a diagnostic tool in primary aldosteronism.

Primary aldosteronism (PA) causes 5-10% of hypertension cases, but only a minority of patients are currently diagnosed and treated because of a complex, stepwise, and partly invasive workup. We tested the performance of urine steroid metabolomics, the computational analysis of 24-hour urine steroid metabolome data by machine learning, for the identification and subtyping of PA. Mass spectrometry-based multi-steroid profiling was used to quantify the excretion of 34 steroid metabolites in 24-hour urine samples from 158 adults with PA (88 with unilateral PA [UPA] due to aldosterone-producing adenomas [APAs]; 70 with bilateral PA [BPA]) and 65 sex- and age-matched healthy controls. All APAs were resected and underwent targeted gene sequencing to detect somatic mutations associated with UPA. Patients with PA had increased urinary metabolite excretion of mineralocorticoids, glucocorticoids, and glucocorticoid precursors. Urine steroid metabolomics identified patients with PA with high accuracy, both when applied to all 34 or only the three most discriminative steroid metabolites (average areas under the receiver-operating characteristics curve [AUCs-ROC] 0.95-0.97). Whilst machine learning was suboptimal in differentiating UPA from BPA (average AUCs-ROC 0.65-0.73), it readily identified APA cases harbouring somatic KCNJ5 mutations (average AUCs-ROC 0.79-85). These patients showed a distinctly increased urine excretion of the hybrid steroid 18-hydroxycortisol and its metabolite 18-oxo-tetrahydrocortisol, the latter identified by machine learning as by far the most discriminative steroid. In conclusion, urine steroid metabolomics is a non-invasive candidate test for the accurate identification of PA cases and KCNJ5-mutated APAs.

Pathology and gene mutations of aldosterone-producing lesions.

The human adrenal cortex secretes aldosterone and cortisol as major corticosteroids. For their production, CYP11B2 and CYP11B1 catalyze the last steps in the syntheses of aldosterone and cortisol, respectively. In our previous study, CYP11B2 was the first successfully purified from rat adrenals and human clinical samples and then was proved to be aldosterone synthase. We demonstrated the immunohistochemistry for CYP11B2 of both rats and humans and applied it clinically to visualize the functional histology of aldosterone-producing adenoma (APA) causing primary aldosteronism (PA). We discovered aldosterone-producing cell clusters (APCCs) and possible APCC-to-APA transitional lesions (pAATLs) and further visualized aldosterone-producing lesions for rare forms of PA including familial hyperaldosteronism type 3 and novel non-familial juvenile PA. Here we review the history of our research on aldosterone-producing lesions.

Role of Adrenal Vein Sampling in Guiding Surgical Decision in Primary Aldosteronism.

Adrenal vein sampling (AVS) is recommended for subtyping primary aldosteronism (PA) to identify lateralized or bilateral sources of aldosterone excess, allowing for better decision-making in regard to medical or surgical management on a case-by-case basis. To date, no consensus exists on protocols to be used during AVS, especially concerning sampling techniques, the timing of sampling, and whether or not to use adrenocorticotropic hormone (ACTH) stimulation. Interpretation criteria for selectivity, lateralization, and contralateral suppression vary from one expert center to another, with some favoring strict cut-offs to others being more permissive. Clinical and biochemical post-operative outcomes can also be influenced by AVS criteria utilized to indicate surgical therapy.In this review, we reanalyze studies on AVS highlighting the recent pathological findings of frequent micronodular hyperplasia adjacent to a dominant aldosteronoma (APA) overlapping with bilateral idiopathic hyperaldosteronism (IHA) etiologies, as opposed to the less frequent unilateral single aldosteronoma. The variable expression of melanocortin type 2 receptors in the nodules and hyperplasia may explain the frequent discordance in lateralization ratios between unstimulated and ACTH- stimulated samples. We conclude that aldosterone values collected during simultaneous bilateral sampling, both at baseline and post-ACTH stimulation, are required to adequately evaluate selectivity, lateralization, and contralateral suppression during AVS, to better identify all patients with PA that can benefit from a surgical indication. Recommended cut-offs for each ratio are also presented.

Role of NCC in the pathophysiology of hypertension in primary aldosteronism.

PURPOSE OF REVIEW: An increasing amount of evidence points out to a role for the thiazide-sensitive Na+:Cl- cotransporter, NCC, in the blood pressure alterations observed in conditions of pathologically high or pathologically low aldosterone. Here, we briefly review this evidence that is changing our perception of the pathophysiology of primary aldosteronism. RECENT FINDINGS: Although initially NCC was thought to be a direct target of aldosterone, more recent evidence suggests that NCC is only indirectly regulated by aldosterone, at least in a chronic setting. Aldosterone-induced changes in plasma K+ concentration that are prompted by the modulation of K+ secretion in principal cells of the connecting tubule and collecting duct are actually responsible for the modulation of NCC in conditions of altered aldosterone levels. A mounting amount of evidence suggests that this indirect effect of aldosterone on NCC may be key to produce the blood pressure alterations observed in aldosterone excess or aldosterone deficit. Finally, recent insights into the molecular pathways involved in NCC modulation by K+ are briefly reviewed. SUMMARY: The evidence reviewed here suggests that correction of K+ alterations in patients with hyper or hypoaldosteronism may substantially affect blood pressure levels. Mechanistically, this may be related to the K+-mediated modulation of NCC.

Primary Aldosteronism: Spatial Multiomics Mapping of Genotype-Dependent Heterogeneity and Tumor Expansion of Aldosterone-Producing Adenomas.

BACKGROUND: Primary aldosteronism is frequently caused by an adrenocortical aldosterone-producing adenoma (APA) carrying a somatic mutation that drives aldosterone overproduction. APAs with a mutation in KCNJ5 (APA-KCNJ5MUT) are characterized by heterogeneous CYP11B2 (aldosterone synthase) expression, a particular cellular composition and larger tumor diameter than those with wild-type KCNJ5 (APA-KCNJ5WT). We exploited these differences to decipher the roles of transcriptome and metabolome reprogramming in tumor pathogenesis. METHODS: Consecutive adrenal cryosections (7 APAs and 7 paired adjacent adrenal cortex) were analyzed by spatial transcriptomics (10x Genomics platform) and metabolomics (in situ matrix-assisted laser desorption/ionization mass spectrometry imaging) co-integrated with CYP11B2 immunohistochemistry. RESULTS: We identified intratumoral transcriptional heterogeneity that delineated functionally distinct biological pathways. Common transcriptomic signatures were established across all APA specimens which encompassed 2 distinct transcriptional profiles in CYP11B2-immunopositive regions (CYP11B2-type 1 or 2). The CYP11B2-type 1 signature was characterized by zona glomerulosa gene markers and was detected in both APA-KCNJ5MUT and APA-KCNJ5WT. The CYP11B2-type 2 signature displayed markers of the zona fasciculata or reticularis and predominated in APA-KCNJ5MUT. Metabolites that promote oxidative stress and cell death accumulated in APA-KCNJ5WT. In contrast, antioxidant metabolites were abundant in APA-KCNJ5MUT. Finally, APA-like cell subpopulations-negative for CYP11B2 gene expression-were identified in adrenocortical tissue adjacent to APAs suggesting the existence of tumor precursor states. CONCLUSIONS: Our findings provide insight into intra- and intertumoral transcriptional heterogeneity and support a role for prooxidant versus antioxidant systems in APA pathogenesis highlighting genotype-dependent capacities for tumor expansion.

The Effect of Aldosterone on Cardiorenal and Metabolic Systems.

Aldosterone, a vital hormone of the human body, has various pathophysiological roles. The excess of aldosterone, also known as primary aldosteronism, is the most common secondary cause of hypertension. Primary aldosteronism is associated with an increased risk of cardiovascular disease and kidney dysfunction compared to essential hypertension. Excess aldosterone can lead to harmful metabolic and other pathophysiological alterations, as well as cause inflammatory, oxidative, and fibrotic effects in the heart, kidney, and blood vessels. These alterations can result in coronary artery disease, including ischemia and myocardial infarction, left ventricular hypertrophy, heart failure, arterial fibrillation, intracarotid intima thickening, cerebrovascular disease, and chronic kidney disease. Thus, aldosterone affects several tissues, especially in the cardiovascular system, and the metabolic and pathophysiological alterations are related to severe diseases. Therefore, understanding the effects of aldosterone on the body is important for health maintenance in hypertensive patients. In this review, we focus on currently available evidence regarding the role of aldosterone in alterations of the cardiovascular and renal systems. We also describe the risk of cardiovascular events and renal dysfunction in hyperaldosteronism.

An Abbreviated History of Aldosterone Metabolism, Current and Future Challenges.

The initial isolation of adrenal steroids from large quantities of animal adrenals resulted in an amorphous fraction resistant to crystallization and identification and had potent effects on electrolyte transport. Aldosterone was eventually isolated and identified in the fraction and was soon shown to cause hypertension when in excess. The autonomous and excessive production of aldosterone, primary aldosteronism, is the most common cause of secondary hypertension. Aldosterone is metabolized in the liver and kidney, and its metabolites are conjugated with glucuronic acid for excretion. The most common liver metabolite is 3α,5ß-tetrahydroaldosterone-3-glucuronide, while that of the kidney is aldosterone-18-oxo-glucuronide. In terms of their value, especially the aldosterone-18-oxo-glucuronide, is commonly used for the diagnosis of primary aldosteronism because they provide an integrated value of the total daily production of aldosterone. Conversion of aldosterone to 18-oxo-glucuronide is impeded by drugs, like some common non-steroidal anti-inflammatory drugs that compete for UDP-glucuronosyltransferase-2B7, the most important glucuronosyltransferase for aldosterone metabolism. Tetrahydroaldosterone is the most abundant metabolite and the most reliable for the diagnosis of primary aldosteronism, but it is not commonly measured.

Phosphoproteomics Reveals the Wolframin-Calcium Axis as an Important Pathogenic Signaling Node in Primary Aldosteronism.

BACKGROUND: Aldosterone-producing adenoma (APA) is a benign adrenal tumor with autonomous aldosterone production which causes hypertension and excess cardiovascular risk. Protein phosphorylation regulates aldosterone secretion from adrenal cortical cells, but how signaling networks are remodeled in APA remains unknown. METHODS: We performed an integrated proteomic and phosphoproteomic profiling of 15 APA and 10 matched nonfunctioning adrenocortical tumors (NFAT) based on the 4-dimensional label-free technique. We further validated our main findings in enlarged APA samples, mice, and adrenocortical cell line. RESULTS: The proteomic and phosphoproteomic profiling of APA and NFAT quantified 5989 proteins and 9011 phosphopeptides. We highlighted differentially expressed and phosphorylated proteins which modulated aldosterone synthesis and secretion from APA. As intracellular calcium is the central signal for aldosterone synthesis, our integrated calcium signaling network implicated wolframin in the control of calcium influx and CYP11B2 (aldosterone synthase) activation in APA (ratio of wolframin expression in APA to NFAT: 6.411, P<0.001). Among 97 APA cases for validation, a higher expression level of wolframin was associated with a higher plasma aldosterone concentration postcaptopril challenge test and a higher systolic blood pressure. In vitro, the secretion of aldosterone was enhanced by wolframin overexpression, while aldosterone secretion in response to potassium or angiotensin II was inhibited by the knockdown of wolframin. Further in vivo and in vitro data demonstrated the wolframin-calcium axis as an important regulator of CYP11B2 expression and aldosterone production. CONCLUSIONS: Wolframin is a regulatory protein in aldosterone hypersecretion. Remodeled calcium transportation and mitochondrial function are involved in wolframin-related aldosterone secretion.

TSPAN12 (Tetraspanin 12) Is a Novel Negative Regulator of Aldosterone Production in Adrenal Physiology and Aldosterone-Producing Adenomas.

BACKGROUND: Aldosterone-producing adenomas (APAs) are a major cause of primary aldosteronism, a condition of low-renin hypertension, in which aldosterone overproduction is usually driven by a somatic activating mutation in an ion pump or channel. TSPAN12 is differentially expressed in different subgroups of APAs suggesting a role in APA pathophysiology. Our objective was to determine the function of TSPAN12 (tetraspanin 12) in adrenal physiology and pathophysiology. METHODS: APA specimens, pig adrenals under dietary sodium modulation, and a human adrenocortical cell line HAC15 were used for functional characterization of TSPAN12 in vivo and in vitro. RESULTS: Gene ontology analysis of 21 APA transcriptomes dichotomized according to high versus low TSPAN12 transcript levels highlighted a function for TSPAN12 related to the renin-angiotensin system. TSPAN12 expression levels in a cohort of 30 APAs were inversely correlated with baseline plasma aldosterone concentrations (R=-0.47; P=0.009). In a pig model of renin-angiotensin system activation by dietary salt restriction, TSPAN12 mRNA levels and TSPAN12 immunostaining were markedly increased in the zona glomerulosa layer of the adrenal cortex. In vitro stimulation of human adrenocortical human adrenocortical cells with 10 nM angiotensin II for 6 hours caused a 1.6-fold±0.13 increase in TSPAN12 expression, which was ablated by 10 µM nifedipine (P=0.0097) or 30 µM W-7 (P=0.0022). Gene silencing of TSPAN12 in human adrenocortical cells demonstrated its inverse effect on aldosterone secretion under basal and angiotensin II stimulated conditions. CONCLUSIONS: Our findings show that TSPAN12 is a negative regulator of aldosterone production and could contribute to aldosterone overproduction in primary aldosteronism.

Secondary diabetes mellitus due to primary aldosteronism.

Primary aldosteronism (PA) and diabetes mellitus (DM) are clinical conditions that increase cardiovascular risk. Approximately one in five patients with PA have DM. Nevertheless, the pathophysiology linking these two entities is not entirely understood. In addition, the majority of patients with PA have glucocorticoid co-secretion, which is associated with increased risk of impaired glucose homeostasis. In the present review, we aim to comprehensively discuss all the available research data concerning the interplay between mineralocorticoid excess and glucose metabolism, with separate analysis of the sequalae in muscle, adipose tissue, liver and pancreas. Aldosterone binds both mineralocorticoid and glucocorticoid receptors and amplifies tissue glucocorticoid activity, via 11-ß-hydroxysteroid dehydrogenase type 1 stimulation. A clear classification of the molecular events as per specific receptor in insulin-sensitive tissues is impossible, while their synergistic interaction is plausible. Furthermore, aldosterone induces oxidative stress and inflammation, perturbs adipokine expression, thermogenesis and lipogenesis in adipose tissue, and increases hepatic steatosis. In pancreas, enhanced oxidative stress and inflammation of beta cells, predominantly upon glucocorticoid receptor activation, impair insulin secretion. No causality between hypokalemia and impaired insulin response is yet proven; in contrast, hypokalemia appears to be implicated with insulin resistance and hepatic steatosis. The superior efficacy of adrenalectomy in ameliorating glucose metabolism vs. mineralocorticoid receptor antagonists in clinical studies highlights the contribution of non-mineralocorticoid receptor-mediated mechanisms in the pathophysiologic process. The exact role of hypokalemia, the mechanisms linking mineralocorticoid excess with hepatic steatosis, and possible disease-modifying role of pioglitazone warrant further studies.

Spontaneous Remission of Primary Aldosteronism with Mineralocorticoid Receptor Antagonist Therapy: A Review.

In this review, we describe previous basic and clinical studies on autonomous aldosterone production. Over the past decades, mineralocorticoid receptor antagonists (MRAs) have been found to concentration-dependently inhibit steroidogenesis in different degrees. However, many studies have proven the suppressive effects of MRAs on the activities of hormone synthase. The probable factors of cytochrome P-450 reduction, both in microsomes and mitochondria, have also been considered: (1) one of the spironolactone metabolite forms had destructive function, except canrenone, (2) 7α-thio-spironolactone was an obligatory intermediate in the spironolactone-induced CYP450 decrease, and (3) the contributing steroids should have 7α-methylthio or 7α-methylsulfone groups. In previous clinical research, spironolactone-body-containing cells showed a type II pattern of enzyme activity (i.e., enhanced 3ß-hydroxysteroid dehydrogenase, glucose-6-phosphate, and NADP-isocitrate dehydrogenase activities and weaken succinate dehydrogenase activity), and the subcapsular micronodules composed of spironolactone-body-containing cells also exhibited a type II pattern and excess aldosterone secretion, indicating that the subcapsular micronodules might be the root of aldosterone-producing adenoma. Moreover, combined with the potential impeditive function to aldosterone secretion, a few cases of spontaneous remission of primary aldosteronism, with normal ranges of blood pressure, plasma potassium, plasma renin activity, and aldosterone renin ratio, have been reported after long-term treatment with MRAs.

Two cases of aldosterone and cortisol producing adenoma with different histopathological features: A case report.

RATIONALE: Primary aldosteronism (PA), including aldosterone and cortisol producing adenoma (A/CPA), is the most common trigger of secondary hypertension. The prevalence of A/CPA may be higher than what we could recognize previously with similar studies, but only a few relevant immunohistochemical reports have confirmed this information. Collecting more clinical features and immunohistochemistry data may help us to understand A/CPA, which is very important for avoiding misdiagnosis and improving outcomes in patients with A/CPA. PATIENT CONCERNS: Both individuals included in this study had hypertension for >10 years. Computed tomography scans revealed the presence of adrenal nodules 1 year ago in patient A and 10 months ago in patient B (based on the date of the final version of this report). The relevant clinical features support PA accompanied by subclinical Cushing syndrome. DIAGNOSIS: Aldosterone and cortisol producing adenoma. INTERVENTIONS: The adrenal adenoma on the affected side was removed and pathological examination and immunohistochemistry were performed. Both the patients received short-term hydrocortisone treatment. OUTCOMES: The blood pressure of both patients improved after surgery. Cytochrome P450 (CYP)11B1, CYP11B2, parathyroid hormone receptor 1 (PTH1R), calcium-sensing receptor (CaSR), and vitamin D3 receptor (VD3R) were all positively expressed, but the histopathological features of the expression region differed. LESSONS: The occurrence of A/CPA may be related to calcium metabolism disorders. For A/CPA, the diversity in immunohistochemistry suggests many uncertainties regarding the pathogenesis of the disease. A/CPA should be considered in new clinical and pathological classifications of PA to gain more attention from the medical community.

Primary aldosteronism: Pathophysiological mechanisms of cell death and proliferation.

Primary aldosteronism is the most common surgically curable form of hypertension. The sporadic forms of the disorder are usually caused by aldosterone overproduction from a unilateral adrenocortical aldosterone-producing adenoma or from bilateral adrenocortical hyperplasia. The main knowledge-advances in disease pathophysiology focus on pathogenic germline and somatic variants that drive the excess aldosterone production. Less clear are the molecular and cellular mechanisms that lead to an increased mass of the adrenal cortex. However, the combined application of transcriptomics, metabolomics, and epigenetics has achieved substantial insight into these processes and uncovered the evolving complexity of disrupted cell growth mechanisms in primary aldosteronism. In this review, we summarize and discuss recent progress in our understanding of mechanisms of cell death, and proliferation in the pathophysiology of primary aldosteronism.

Changes of the CYP11B2 Expressing Zona Glomerulosa in Human Adrenals From Birth to 40 Years of Age.

BACKGROUND: Aldosterone synthase (CYP11B2) antibodies for immunohistochemistry, enables to visualize aldosterone-producing zona glomerulosa (ZG), aldosterone-producing micronodules, and aldosterone-producing adenomas. The architecture of the ZG differs in old versus young age but the evolution of the changes is not well known. The pathogenesis of aldosterone-producing micronodules and aldosterone-producing adenomas is still unclear and research on the ZG in young populations is limited. In this study, we elucidate changes in human ZG with age by quantifying the CYP11B2 expression. METHODS: We collected 83 human adrenal glands from 57 autopsy cases aged 0 to 40 years old. In 26 cases, both adrenals were available. We performed immunohistochemistry targeting CYP11B2 and quantified the relative CYP11B2 expressing area, CYP11B2 continuity, the mean gap length between CYP11B2-expressing areas and the maximum extension of CYP11B2 area (depth). RESULTS: We found a negative correlation between age and the relative CYP11B2 expressing area, a negative correlation between age and CYP11B2 continuity, a positive correlation between age and mean gap length, and a positive correlation between age and maximum CYP11B2 depth. The changes in expression patterns of relative CYP11B2 expressing area, CYP11B2 continuity and mean gap length were seen in both adrenals of the same autopsy case. CONCLUSIONS: The decline of relative CYP11B2 expressing ZG area and continuity may indicate involution of the ZG, which is supported by an increase of gaps and maximum CYP11B2 depth indicating clustering, comparable to formation of aldosterone-producing micronodules. The similarities in both adrenals from the same case indicate that these changes occur bilaterally.

Characterization of Aldosterone-producing Cell Cluster (APCC) at Single-cell Resolution.

CONTEXT: The adrenal cortex consists of zona glomerulosa (ZG), fasciculata (ZF), and reticularis. Aldosterone-producing cell clusters (APCCs) that strongly express aldosterone synthase (CYP11B2) are frequently found in adult adrenals and harbor somatic mutations that are also detected in aldosterone-producing adenomas (APAs). Primary aldosteronism is mainly caused by APAs or idiopathic hyperaldosteronism (IHA). We presume that APCCs are causing IHA and are precursors of APAs. However, the gene expression characteristics and especially the development of APCCs are not well understood. OBJECTIVE: This study aimed to analyze the transcriptome of APCCs at single-cell resolution and infer the developmental trajectory. METHODS: Single-cell RNA sequencing (scRNA-seq) of 2 adult adrenals was performed. RESULTS: Immunohistochemical analyses confirmed the 2 adrenals had APCCs. scRNA-seq data of 2928 adrenal cells were obtained and 1765 adrenocortical cells were identified based on unsupervised clustering and the marker gene expression. The adrenocortical cells were divided into 6 clusters, of which 3 clusters (923 cells) were composed of APCC/ZG cells. By further subclustering, the APCC/ZG cells were divided into 3 clusters (clusters C1, C2, and C3), we finally identified APCC cluster (C3) and ZG cluster (C1). Cluster C2 seemed to be ZG-to-ZF transitional cells. RNA velocity analysis inferred the developmental direction from cluster ZG-cluster-C1 to APCC-cluster-C3. The scRNA-seq additionally revealed that many CYP11B2-positive cells were positive for CYP11B1 and/or CYP17A1, which were essential for cortisol but not for aldosterone production. CONCLUSIONS: Our results revealed the gene expression characteristics of APCC at single-cell resolution and show that some ZG cells remodel to APCC.