Age-Related Autonomous Aldosteronism

Integration of mitochondrial gene expression and immune landscape in acute kidney injury prediction

BACKGROUND

Acute kidney injury (AKI) is a life-threatening condition with limited early biomarkers. Mitochondrial dysfunction is central to AKI pathophysiology, yet its potential for predicting AKI remains underexplored.

METHODS

Gene expression data from three publicly available AKI datasets (GSE30718, GSE61739, and GSE139061) were analyzed to identify differentially expressed genes (DEGs). A set of 11 mitochondrial-related genes was selected and used to construct a mitochondrial risk score (MRS) model via Lasso and elastic net regression. The model was validated across multiple datasets. Immune infiltration was assessed using the xCell algorithm to explore the relationship between MRS and immune cell dynamics in AKI. Stable HK-2 cells were constructed of XRCC3 knockdown and overexpression to investigate the effects of XRCC3 on cell activities. Additionally, the impact of XRCC3 on mitochondrial structure and function was examined in vivo and in vitro.

RESULTS

Eleven mitochondrial-related genes were consistently dysregulated across all datasets. PCA demonstrated a clear separation between AKI and normal samples. Functional enrichment analysis revealed that upregulated genes were linked to extracellular matrix remodeling and stress responses, while downregulated genes were associated with mitochondrial dysfunction. The MRS model showed strong predictive performance. We found that XRCC3 significantly promoted the activities of HK-2 cells and improved the integrity of mitochondrial structure and function in vivo and in vitro.

CONCLUSION

The mitochondrial gene-based MRS model is a robust tool for predicting AKI. Our findings underscore the critical role of mitochondrial dysfunction and immune modulation in AKI, offering potential avenues for targeted therapeutic strategies.

Long-term effects of maternal protein restriction on adrenal proteomic profile and steroidogenesis in male offspring rats

Maternal protein restriction (MPR) can significantly affect offspring's early development and aging, impacting several organs, including the adrenal glands. This study evaluated the adrenal proteomic profile in male rat offspring exposed to MPR during pregnancy and lactation. Male offspring were divided into two groups: Control (CTR), born to dams fed a normoprotein diet (17 % protein), and Gestational and Lactational Low-Protein (GLLP), born to dams fed a low-protein diet (6 % protein) throughout gestation and lactation, and after received control diet. Offspring were euthanized at postnatal day (PND) 21 or PND 540. Blood samples and adrenal glands were processed for histological, metabolic, molecular, and proteomic assessments. At PND21, the GLLP group exhibited reduced adrenal gland mass and cortical thickness. At PND21, the proteomic landscape showed that the most impacted biological pathways were associated with decreased steroid hormone synthesis, increased glucose metabolism, and stress response. At PND540, the main impacts were increased apoptotic pathway, stress response, and steroid hormone synthesis, with decreased glucose metabolism. At PND 540, the GLLP group showed higher adrenal collagen content and elevated apoptosis. Age-related changes included decreased peroxiredoxin 3 and increased expression of aldosterone synthase (Cyp11b2). Furthermore, steroid 11-Beta-Hydroxylase (Cyp11b1) expression decreased at PND540, alongside reduced serum aldosterone and elevated serum corticosterone levels. These results suggest that MPR modulates the adrenal glands' proteomic profile, serving as a pivotal mechanism underpinning diverse systemic diseases. It influences adrenal morphophysiology early in life, with long-lasting consequences for cellular stress, immune response, and catabolic pathways in male offspring with aging.

ABCC3 Is a Differential Marker of CYP11B2-Negative Zona Glomerulosa Cells in Human Adrenal Cortex

ATP Binding Cassette Subfamily C Member 3 (ABCC3) is a membrane transporter that exports diverse compounds, influencing drug resistance in cancers and impacting metabolic and malignant diseases. We previously reported ABCC3 upregulation in human adrenal cells under lipid peroxidation-induced oxidative stress. We investigated ABCC3 expression and function in the human adrenal cortex in the context of primary aldosteronism, focusing on its relationship to CYP11B2 (aldosterone synthase) in zona glomerulosa (ZG) cells and aldosterone-producing lesions. ABCC3 expression in aldosterone-producing adenomas (APAs) was markedly reduced compared to the adjacent adrenal cortex, cortisol-producing adenomas, and non-functioning adenomas. The reduction in APAs showed genotypic variability: in APAs harboring KCNJ5 mutations-known drivers of autonomous aldosterone production via altered potassium channel function-ABCC3 mRNA/protein levels were significantly higher than in wild-type KCNJ5 APAs. Spatial transcriptomics and immunofluorescence colocalization revealed an inverse expression pattern between ABCC3 and CYP11B2 (aldosterone synthase) in APAs and aldosterone-producing micronodules (APMs). Notably, high ABCC3 expression was exclusively observed in adrenal ZG cells that lacked CYP11B2 expression. This expression pattern distinguishes ABCC3 from common ZG markers such as KCNJ5 and DAB2, which are expressed across adrenal ZG cells, APMs, and APA tumor cells. In cultured human adrenocortical cells, both angiotensin II stimulation and induced expression of the KCNJ5-L168R mutation resulted in upregulation of CYP11B2 transcription while concomitantly suppressing ABCC3 expression. In conclusion, ABCC3 serves as a novel marker of CYP11B2-negative ZG cells, providing a histopathological tool to differentiate normal adrenal zonation from aldosterone-producing lesions in primary aldosteronism, as well as from cortisol-producing and nonfunctional adenomas.

Mineralocorticoid Receptor Antagonist Use in Hypertension to Prevent Heart Failure

Mineralocorticoid receptor antagonists (MRAs) reduce cardiovascular mortality and heart failure (HF) hospitalizations across the spectrum of HF. Beyond their recognized benefits in patients with established HF, the value of MRA therapy may be undervalued for the prevention of HF in patients with hypertension. Emerging evidence indicates that a substantial proportion of patients considered to have "idiopathic" or "essential" hypertension have mineralocorticoid receptor overactivation by under-recognized mechanisms (such as, primary aldosteronism pathophysiology, cortisol dysregulation, and ligand-independent activation). The recognition that MRAs may address an operative mechanism of HF pathogenesis, and that implementation of therapy early in the course of hypertension may prevent the incidence of HF, suggests a new strategy to prevent HF that warrants further investigation. This review summarizes new evidence and theories which suggest that increased use of MRAs in hypertension may decrease incident HF by addressing common and under-recognized mechanisms of mineralocorticoid receptor overactivation.

Antihypertensive drug treatment: are we ready for the future?

Treatment of hypertension generally requires multiple antihypertensive drugs. Yet, not all patients are treated adequately, largely because of nonadherence, although drug ineffectiveness and counterbalancing mechanisms may also play a role. Novel antihypertensive drugs have not been introduced for at least one to two decades. Remarkably, over the last few years, a range of novel compounds is being introduced, acting either on novel targets, or displaying an exceptionally long half-life. The former may help to improve blood pressure lowering, for instance by interfering with counterbalancing mechanisms, while the latter might help to circumvent nonadherence. This review summarizes the latest developments, focusing on novel drugs acting on the endothelin system, the renin-angiotensin-aldosterone system (RAAS), and atrial natriuretic peptide (ANP).

Adrenal aldosterone synthase (CYP11B2) histopathology and its association with disease-induced sudden death: a cross-sectional study

Background

Unidentified cardiovascular risk factors may account for approximately half of sudden deaths, a devastating event with limited preventive tools. We investigated whether adrenal histopathology suggestive of primary aldosteronism, pheochromocytoma, or adrenal masses could explain part of the risk for disease-induced sudden death (DSD).

Methods

In this study, autopsies and histopathological analyses, including aldosterone synthase staining of adrenal glands, were performed on 403 consecutive individuals who experienced sudden death. These individuals were classified into 258 cases of DSD and 144 deaths caused by trauma, suicide, or intoxication, i.e., non-disease-induced sudden death (nDSD). This trial was registered at ClinicalTrials.gov (NCT05446779).

Findings

Adrenal histopathology revealed changes in 31 (7.7%) subjects of the cohort. Of these, the most prevalent findings [25 (6.2%)] were aldosterone-producing adenomas (APA) or nodules (APN), which were associated with myocardial infarction and atherosclerosis at autopsy. Individuals in the DSD group and the subgroup with sudden cardiac death (SCD) were more likely to have APA or APN than individuals in the nDSD group [23 (8.9%) vs. 2 (1.4%), p = 0.002; 16 (8.8%) vs. 2 (1.4%), p = 0.003, respectively]. APA or APN were explanatory factors for DSD (odds ratio [OR] 6.47, 95% confidence interval [CI] 1.40-29.88, p = 0.017) and SCD (OR 10.68, 95% CI 2.02-56.43, p = 0.005). Other findings included two pheochromocytomas, one bilateral adrenal metastasis, and two unilateral adrenal metastases.

Interpretation

In this exploratory study, APA or APN were more frequently seen in DSD and SCD than nDSD cases. Whether primary aldosteronism constitutes a novel risk factor for sudden death warrants further study.

Funding

Finnish State Research funds and independent research foundations: Aarne Koskelo Foundation, the Finnish Kidney Foundation, and the Finnish Foundation for Cardiovascular Research.

Intraprotocol Adrenal Vein Sampling Inconsistencies in Primary Aldosteronism Lateralization

Background Primary aldosteronism can arise from one or both adrenal glands. Adrenal vein sampling (AVS) is the standard of care for identifying patients with lateralized primary aldosteronism who would benefit from surgery. Variability in AVS lateralization has been primarily attributed to cosyntropin use and lateralization index thresholds. Data regarding intraprotocol variability are lacking. Purpose To assess the rates of intraprotocol lateralization inconsistency during simultaneous AVS. Materials and Methods This retrospective cross-sectional study assessed patients with primary aldosteronism who underwent simultaneous AVS at a single tertiary referral center between January 2015 and December 2023. Six sets of adrenal vein and peripheral vein samples were obtained: three baseline samples obtained after cannulation, 5 minutes apart; and three samples obtained between 5 and 30 minutes after cosyntropin stimulation. Patients with successful cannulation and valid hormonal data at all six time points were included. A lateralization index (computed as the aldosterone-to-cortisol ratio between the two adrenal veins, with the highest number as numerator) of at least 4 was considered indicative of lateralized primary aldosteronism. The proportions of baseline and stimulated AVS sets within which one of three lateralization indexes provided different subtype results were assessed. Linear mixed-effects models were used to estimate the between- and within-patient hormonal and lateralization index variances. Results Of 402 patients (median age, 53 years; IQR, 45-63 years; 233 male) included, 129 patients (32.1%) had at least one lateralization index inconsistency. Of these 402 patients, 89 patients (22.1%) had lateralization inconsistencies within the baseline sets, 53 patients (13.2%) within cosyntropin-stimulated sets, and 13 patients (3.2%) in both baseline and cosyntropin-stimulated sets. The highest outlier prevalence occurred in the first (42 patients; 10.4%) and third (33 patients; 8.2%) baseline samples, with roughly twofold-lower rates in the first (23 patients; 5.7%) and last postcosyntropin stimulation samples (4.2%; 17 patients). The absolute change in baseline and cosyntropin-stimulated lateralization index (maximum-minimum lateralization index within a triplicate) was as high as 152.9 and 327.4, respectively. The highest hormonal variability was noted in the adrenal vein producing less aldosterone. Conclusion Almost a third of patients undergoing AVS in triplicate, both before and after cosyntropin stimulation, had intraprotocol discrepancies in lateralization results, with the highest variability occurring within samples obtained without cosyntropin stimulation. © RSNA, 2025 See also the editorial by Georgiades in this issue.

Poor sleep quality was associated with increased plasma aldosterone concentration in community dwellers, a cross-sectional study

Sleep is implicated in circulating aldosterone, whereas effects of overall sleep quality are not characterized. Therefore, we explored relationship of sleep quality with plasma aldosterone concentration (PAC) in general population. We evaluated sleep quality using Pittsburgh sleep quality index (PSQI) and measured PAC in adults cross-sectionally. We divided participants into very good, fairly good, fairly bad and very bad sleepers, compared PAC and log-PAC, and applied linear regression to examine association of PSQI score with log-PAC, in total, gender- and age-stratified (young, middle-aged and old) participants. Sensitivity analysis were performed by excluding hypertension, sleep disordered breathing (SDB), or both. Among 29,499 participants, PAC showed significant increase from very good to very bad sleepers in total (14.3 vs. 14.4 vs. 14.7 vs. 15.8ng/dL), and in male participants (13.1 vs. 13.6 vs. 14.1 vs. 14.9ng/dL), consistent in the young and the middle-aged (P for all < 0.001) and in log PAC of total, in male and in different age groups (P for trend < 0.001). PSQI score showed significant positive association with log-PAC in total (B, 95%CI: 0.007, 0.003-0.010, P < 0.001) in male participants (0.013, 0.008-0.018, P < 0.001), consistent in the young and the middle-aged and in adjusted models. In female, PSQI score showed significant positive association with log-PAC in the old-aged. Sensitivity analysis yielded consistent observation with main analysis. Poor sleep quality is associated with elevated PAC, in young and middle-aged male and in elder female, independent of SDB and hypertension, indicating potential involvement of sleep quality on regulation of circulating aldosterone.

Adrenal cortex senescence: an ageing-related pathology?

The adrenal glands are a pair of endocrine organs that produce and secrete mineralocorticoids, glucocorticoids, sex hormones, adrenaline, and noradrenaline. They have a vital role in a range of physiological processes including regulating electrolyte balance, blood pressure and metabolism, immunomodulation, sexual development and the stress response. Adrenal cortex senescence describes the ageing-related decline in the normal functioning of the adrenal cortex, characterised by an alteration in the output of adrenal cortical hormones, in particular reduced secretion of dehydroepiandrosterone (DHEA) and sulfated dehydroepiandrosterone (DHEAS). Such endocrine aberrations may be implicated in adverse clinical outcomes including mood disturbances, impairment in cognitive functioning, metabolic dysfunction and osteopenia. This paper shall address whether adrenal cortex senescence should be recognised as an ageing-related pathology, which has recently been defined as one that develops and/or progresses with increasing chronological age, that is associated with, or contributes to, functional decline, and is evidenced by studies in humans.

Unmasking primary aldosteronism: Transforming disease management with advanced steroid profiling

Primary aldosteronism (PA) is traditionally thought to result from the overproduction of aldosterone which is unregulated by the renin-angiotensin system. It leads to a significantly increased risk of cardiovascular and metabolic complications as compared to primary hypertension. However, approximately one-third of patients diagnosed with PA according to the traditional guidelines have been found to exhibit low aldosterone levels and other steroid hormones may also play a potentially critical role in PA development. Early diagnosis of PA remains challenging due to low screening rates and the complex diagnostic procedures. The need for invasive adrenal vein sampling for PA subtyping also leads to a dilemma in therapeutic strategy selection. With advances in techniques, an increasing number of steroid hormones have been discovered to be associated with PA, potentially optimizing the PA diagnostic procedures. Herein, we review the cutting-edge advances in steroid hormones, including aberrant hormone synthesis and metabolism related to the pathophysiological development of PA, quantitative assays, and potential clinical value. Mass spectrometry provides a robust technical foundation for the simultaneous profiling of a panel of steroid hormones. Steroid hormone profiling combined with machine learning algorithms holds great research promise for facilitating early diagnosis and minimally invasive subtyping of PA. Thus, current progress and future expectations in combining steroid hormones with advanced technologies for early disease diagnosis and management are also reviewed. Research Agenda. 1) Identify changes in steroid hormones and the underlying biochemical mechanisms associated with PA. 2) Investigate the role of advanced mass spectrometry techniques in steroid hormone profiling. 3) Discuss current advances and future expectations in combining machine learning algorithms with MS-based steroid hormone profiling for PA's systematic and practical management.

Normotensive Primary Aldosteronism - Does it Exist?

Heightened aldosterone levels are associated with increased risk of renal sequelae, cardiovascular morbidity and mortality. Historically, primary aldosteronism is linked to hypertension. However, growing evidence reveals its presence even in normotensive individuals. This review consolidates data from diverse sources, delves into clinical studies of this underexplored condition, discusses the potential mechanisms, and provides a comprehensive and an up-to-date overview of the current state of knowledge. It highlights the evidence and understanding of normotensive primary aldosteronism, summarizes findings, and identifies opportunities for future research in this area. By addressing the clinical evidence, risk of hypertension development and possible mechanisms involved, this review aims to advance the understanding of this distinct form of primary aldosteronism and inspire further research in this emerging field.

Characterizing the Origins of Primary Aldosteronism

BACKGROUND

Renin-independent aldosterone production in normotensive people increases risk for developing hypertension. In parallel, normotensive adrenal glands frequently harbor aldosterone-producing micronodules with pathogenic somatic mutations known to induce primary aldosteronism (PA). A deeper understanding of these phenomena would inform the origins of PA and its role in hypertension pathogenesis.

METHODS

Prospectively recruited normotensives underwent detailed characterization of PA features via the following: oral sodium suppression test to evaluate renin-independent aldosterone production, dexamethasone suppression and adrenocorticotropic hormone-stimulation tests to evaluate adrenocorticotropic hormone-mediated aldosterone production, and 24-hour ambulatory blood pressure monitoring. The magnitude of renin-independent aldosterone production was defined via tertiles of 24-hour urinary aldosterone production during the oral sodium suppression test to create unbiased categorizations of the magnitude of PA. Serum aldosterone, serum 18-hybrid steroids, urine tetrahydroaldosterone (biomarkers of aldosterone synthase activity), urinary potassium, and blood pressure (biomarkers of mineralocorticoid receptor activation) were evaluated across tertiles.

RESULTS

There was a spectrum of autonomous, nonsuppressible, and renin-independent production of aldosterone, 18-hybrid steroids, and 24-hour urinary tetrahydroaldosterone (P-trend <0.01). Correspondingly, there was a continuum of adrenocorticotropic hormone-mediated aldosterone production and 18-hybrid steroid production that also paralleled renin-independent aldosterone production. The spectrum of PA pathophysiology was associated with higher ambulatory daytime systolic BP (P-trend <0.05), even within the normotensive range, and greater urinary potassium excretion (P-trend <0.05), indicating a continuum of mineralocorticoid receptor activation.

CONCLUSIONS

The pathophysiologic continuum of PA, characterized by renin-independent and adrenocorticotropic hormone-mediated aldosterone production, and enhanced aldosterone synthase and mineralocorticoid receptor activity, is evident in normotensive people. These findings provide mechanistic explanations to implicate PA in the pathogenesis of a substantial proportion of hypertension.

Shifting paradigms in primary aldosteronism: reconsideration of screening strategy via integrating pathophysiological insights

Several decades have passed since the description of the first patient with primary aldosteronism (PA). PA was initially classified in two main forms: aldosterone-producing adenoma (APA) and idiopathic hyperaldosteronism (IHA). However, the pathogenesis of PA has now been shown to be far more complex. For this reason, the traditional classification needs to be updated. Given the recent advancements in our understanding of PA pathogenesis, we should reevaluate how frequent PA cases are, beginning with the reconstruction of the screening strategy. Recent studies consistently indicated that PA has been identified in 22% of patients with resistant hypertension and 11% even in normotensives. The frequency is influenced by the screening strategy and should be based on understanding the pathogenesis of PA. Progress has been made to promote our understanding of the pathogenesis of PA by the findings of aldosterone driver mutations, which have been found in normotensives and hypertensives. In addition, much clinical evidence has been accumulated to indicate that there is a spectrum in PA pathogenesis. In this review, we will summarize the recent progress in aldosterone measurement methods based on LC-MS/MS and the current screening strategy. Then, we will discuss the progress of our understanding of PA, focusing on aldosterone driver mutations and the natural history of PA. Finally, we will discuss the optimal strategy to improve screening rate and case detection.

Staining patterns of aldosterone synthase in patients undergoing surgery for primary aldosteronism: Proposal for system of categorization and investigation of clinical and biochemical correlation

BACKGROUND

How aldosterone synthase (CYP11B2) staining patterns impact patient outcomes in those with unilateral primary aldosteronism is not well described. We hypothesized that a system of categorization would benefit future research and that clinical and biochemical outcomes after unilateral adrenalectomy are impacted by different CYP11B2 staining patterns.

METHODS

A retrospective review of patients undergoing adrenalectomy for primary aldosteronism from January 2015 to September 2023 was conducted. Demographics, clinical, and pathologic data were analyzed. A system of categorization of staining patterns was developed. Clinical and biochemical outcomes were compared with staining patterns to assess differences and determine correlation. Descriptive and statistical analyses were performed using SPSS.

RESULTS

Forty-three patients were included. The following CYP11B2 staining patterns were identified: (1) single adenoma; (2) aldosterone producing nodule(s) or micronodule(s); (3) combination of type 1 and type 2; (4) hyperplasia; and (5) aldosterone-producing adrenocortical cancer. In total, 23 of 43 revealed CYP11B2 staining in a single adenoma only. Staining in 3/23 involved a portion of the adenoma. 4/9 patients age <40 had areas of CYP11B2 staining in nonadenomatous tissue. Complete biochemical cure was noted in 37 of 43 (86%) and complete clinical cure in 23.2%. There were no differences between staining pattern and sex, race, or age. CYP11B2 staining pattern did not correlate with early clinical or biochemical outcomes.

CONCLUSION

Adrenalectomy specimens from patients treated for primary aldosteronism reveal multiple CYP11B2 staining patterns, including in nonadenomatous tissue in many patients. The impact of these patterns on clinical outcomes requires additional investigation. Uniform categorization of staining patterns will allow for consistent reporting across studies.

Emerging concepts on the FGF23 regulation and activity

Fibroblast growth factor 23 (FGF23) discovery has provided new insights into the regulation of Pi and Ca homeostasis. It is secreted by osteoblasts and osteocytes, and acts mainly in the kidney, parathyroid, heart, and bone. The aim of this review is to highlight the current knowledge on the factors modulating the synthesis of FGF23, the canonical and non-canonical signaling pathways of the hormone, the role of FGF23 in different pathophysiological conditions, and the anti-FGF23 therapy. This is a narrative review based on the search of PubMed database in the range of years 2000-2023 using the keywords local and systemic regulators of FGF23 synthesis, FGF23 receptors, canonical and non-canonical pathways, pathophysiological conditions and FGF23, and anti-FGF23 therapy, focusing the data on the molecular mechanisms. The regulation of FGF23 synthesis is complex and multifactorial. It is regulated by local factors and systemic regulators mainly involved in bone mineralization. The excessive FGF23 production is associated with different congenital diseases and with diseases occurring with a secondary high FGF23 production such as in chronic disease kidney and tumor-induced osteomalacia (TIO). The anti-FGF23 therapy appears to be useful to treat chromosome X-linked hypophosphatemia and TIO, but there are doubts about the handle of excessive FGF23 production in CKD. FGF23 biochemistry and pathophysiology are generating a plethora of knowledge to reduce FGF23 bioactivity at many levels that might be useful for future therapeutics of diseases associated with high-serum FGF23 levels.

Circulating miRNAs and Machine Learning for Lateralizing Primary Aldosteronism

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Resistant Hypertension in Older Adults

Resistant hypertension is a complex disorder that requires a comprehensive evaluation of several patient characteristics. Attention should be paid to medication and lifestyle adherence, and investigation into potential secondary causes of resistant hypertension should occur as clinically indicated. Moreover, a shared, multidisciplinary decision-making approach with the patient, specialized care providers, and family members may enhance blood pressure control.

Somatic Mutations in MCOLN3 in Aldosterone-Producing Adenomas cause Primary Aldosteronism

Primary aldosteronism is characterized by renin-independent hyperaldosteronism that originates from aldosterone-producing lesions in the adrenal glands. Under physiological conditions, aldosterone synthase ( CYP11B2 ) expression is confined to the adrenal zona glomerulosa where it catalyzes the final reaction yielding aldosterone. The regulation of CYP11B2 transcription depends on the control of cellular membrane potential and cytosolic calcium activity. In primary aldosteronism, aldosterone-producing adenomas (APAs) are characterized by disrupted regulation of CYP11B2 expression resulting in autonomous biosynthesis of aldosterone. These lesions often harbor aldosterone-driver somatic mutations in genes encoding ion transporters/channels/pumps that increase cytosolic calcium activity causing increased CYP11B2 expression and aldosterone biosynthesis. We investigated APAs devoid of known somatic mutations and detected a missense mutation and a deletion-insertion variant in MCOLN3 which encodes for mucolipin-3 (TRPML3) - a highly conserved inwardly-rectifying, cation-permeable channel. These MCOLN3 mutations were identified in three APAs derived from male patients with primary aldosteronism: p. Y391D and p.N411_V412delinsI. Both mutations are located near the ion pore and selectivity filter of TRPML3. This is the first report of disease-causing MCOLN3 mutations in humans. Functional studies suggest MCOLN3 Y391D might directly or indirectly via membrane depolarization alter calcium influx of transfected adrenocortical cells, resulting in increased CYP11B2 transcription and aldosterone production. This study implicates mutated MCOLN3 as a driver of aldosterone excess in primary aldosteronism.

Significance Statement

Primary aldosteronism is a common but under-diagnosed endocrine disease that contributes to global hypertension burden and cardiovascular mortality and morbidity. Hyperaldosteronism in primary aldosteronism is mainly caused by adrenal lesions harboring somatic mutations that disrupt intracellular calcium levels and consequently aldosterone synthase expression and aldosterone production. Majority of these mutations have been identified in genes encoding ion transporters/channels/pumps. Herein, we report the first disease-causing somatic mutations in human MCOLN3 in aldosterone-producing adenomas (APAs) devoid of known mutations. In vitro investigations showed the MCOLN3 variant (p.Y391D) caused an influx of cytosolic calcium in adrenocortical cells and the subsequent increase in aldosterone synthase and aldosterone biosynthesis.

Update on Low-Renin Hypertension: Current Understanding and Future Direction

Low-renin hypertension is common and affects 1 in 4 people with hypertension. Understanding the different causes and management of low-renin hypertension is becoming increasingly relevant as renin measurements are more widely ordered in clinical practice. Importantly, many people with low-renin hypertension do not fit traditional definitions of known causes, and the approach to management of these people is not unclear. This review provides an overview of our evolving understanding of the causes of low-renin hypertension, the expanding spectrums of pathophysiology, key differentiating characteristics, distinct management strategies, and highlights our knowledge gaps. It is important to distinguish the underlying pathophysiology of an individual with low-renin hypertension to individualize treatment.

Targeting Cell Senescence and Senolytics: Novel Interventions for Age-Related Endocrine Dysfunction

Multiple changes occur in hormonal regulation with aging and across various endocrine organs. These changes are associated with multiple age-related disorders and diseases. A better understanding of responsible underling biological mechanisms could help in the management of multiple endocrine disorders over and above hormone replacement therapy (HRT). Cellular senescence is involved in multiple biological aging processes and pathologies common in elderly individuals. Cellular senescence, which occurs in many older individuals but also across the lifespan in association with tissue damage, acute and chronic diseases, certain drugs, and genetic syndromes, may contribute to such endocrine disorders as osteoporosis, metabolic syndrome, and type 2 diabetes mellitus. Drugs that selectively induce senescent cell removal, "senolytics,", and drugs that attenuate the tissue-destructive secretory state of certain senescent cells, "senomorphics," appear to delay the onset of or alleviate multiple diseases, including but not limited to endocrine disorders such as diabetes, complications of obesity, age-related osteoporosis, and cancers as well as atherosclerosis, chronic kidney disease, neurodegenerative disorders, and many others. More than 30 clinical trials of senolytic and senomorphic agents have already been completed, are underway, or are planned for a variety of indications. Targeting senescent cells is a novel strategy that is distinct from conventional therapies such as HRT, and thus might address unmet medical needs and can potentially amplify effects of established endocrine drug regimens, perhaps allowing for dose decreases and reducing side effects.

Evaluating the role of aldosterone synthesis on adrenal cell fate

Hypertension affects one-third of the adult population worldwide, with primary aldosteronism (PA) accounting for at least 5-10% of these cases. The aldosterone synthase enzyme (CYP11B2) plays a pivotal role in PA manifestation, as increased expression of CYP11B2 leads to excess aldosterone synthesis. Physiological expression of CYP11B2 in humans is normally limited to cells of the adrenal zona glomerulosa under tight homeostatic regulation. In PA, however, there are CYP11B2-positive lesions in the adrenal cortex that autonomously secrete aldosterone, highlighting the dysregulation of adrenal cortex zonation and function as a key aspect of PA pathogenesis. Thus, this review aims to summarize the development of the adrenal glands, the key regulators of adrenal cortex homeostasis, and the dysregulation of this homeostasis. It also discusses the development of CYP11B2 inhibitors for therapeutic use in patients with hypertension, as well as the current knowledge of the effects of CYP11B2 inhibition on adrenal cortex homeostasis and cell fate. Understanding the control of adrenal cell fate may offer valuable insights into both the pathogenesis of PA and the development of alternative treatment approaches for PA.

Self-Reported Sodium Intake and Sodium Vulnerability in Heart Failure With Preserved Ejection Fraction

OBJECTIVE

To determine the pathophysiologic and prognostic meaning of patient self-reported sodium intake in heart failure (HF) with preserved ejection fraction (HFpEF).

METHODS

This cohort analysis used data from the Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist (TOPCAT) trial of patients enrolled in the Americas. Tertiles of baseline self-reported sodium intake were used to assess the relationship between self-reported sodium intake and clinical presentation/outcome and interactions with treatment effect of spironolactone.

RESULTS

Self-reported sodium intake of 1748 patients with HFpEF included in TOPCAT were divided according to tertiles of sodium intake (47% low, 35% moderate, and 18% high sodium intake). After covariate adjustment, lower self-reported sodium intake was associated with higher risk of HF hospital admission (P=.009). Patients with lower sodium intake had higher E-wave velocity, left ventricular end diastolic volume, and estimated plasma volume (P<.001). Lower sodium intake was associated with a larger treatment effect of spironolactone on HF hospitalizations (hazard ratio, 0.69; 95% CI, 0.53 to 0.91) vs the highest tertile (hazard ratio, 1.37; 95% CI, 0.79 to 2.38; interaction P=.030). In addition, linear mixed models indicated larger reductions in blood pressure, dyspnea, and edema (all interaction P<.001) in patients with lower sodium intake receiving spironolactone.

CONCLUSION

Low self-reported sodium level in HFpEF is associated with higher risk of HF hospital admissions and may indicate a sodium-vulnerable state; patients should not be falsely reassured that they are in a lower risk category despite greater adherence to medical recommendations.

Single-cell and spatial transcriptomics analysis of human adrenal aging

OBJECTIVE

The human adrenal cortex comprises three functionally and structurally distinct layers that produce layer-specific steroid hormones. With aging, the human adrenal cortex undergoes functional and structural alteration or "adrenal aging", leading to the unbalanced production of steroid hormones. Given the marked species differences in adrenal biology, the underlying mechanisms of human adrenal aging have not been sufficiently studied. This study was designed to elucidate the mechanisms linking the functional and structural alterations of the human adrenal cortex.

METHODS

We conducted single-cell RNA sequencing and spatial transcriptomics analysis of the aged human adrenal cortex.

RESULTS

The data of this study suggest that the layer-specific alterations of multiple signaling pathways underlie the abnormal layered structure and layer-specific changes in steroidogenic cells. We also highlighted that macrophages mediate age-related adrenocortical cell inflammation and senescence.

CONCLUSIONS

This study is the first detailed analysis of the aged human adrenal cortex at single-cell resolution and helps to elucidate the mechanism of human adrenal aging, thereby leading to a better understanding of the pathophysiology of age-related disorders associated with adrenal aging.

Multifocal, Asymmetric Bilateral Primary Aldosteronism Cannot be Excluded by Strong Adrenal Vein Sampling Lateralization: An International Retrospective Cohort Study

BACKGROUND

Primary aldosteronism (PA) has been broadly dichotomized into unilateral and bilateral forms. Adrenal vein sampling (AVS) lateralization indices (LI) ≥2 to 4 are the standard-of-care to recommend unilateral adrenalectomy for presumed unilateral PA. We aimed to assess the rates and characteristics of residual PA after AVS-guided adrenalectomy.

METHODS

We conducted an international, retrospective, cohort study of patients with PA from 7 referral centers who underwent unilateral adrenalectomy based on LI≥4 on baseline and/or cosyntropin-stimulated AVS. Aldosterone synthase (CYP11B2) immunohistochemistry and next generation sequencing were performed on available formalin-fixed paraffin-embedded adrenal tissue.

RESULTS

The cohort included 283 patients who underwent AVS-guided adrenalectomy, followed for a median of 326 days postoperatively. Lack of PA cure was observed in 16% of consecutive patients, and in 22 patients with lateralized PA on both baseline and cosyntropin-stimulated AVS. Among patients with residual PA postoperatively, 73% had multiple CYP11B2 positive areas within the resected adrenal tissue (versus 23% in those cured), wherein CACNA1D mutations were most prevalent (63% versus 33% in those cured). In adjusted regression models, independent predictors of postoperative residual PA included Black versus White race (odds ratio, 5.10 [95% CI, 1.45-17.86]), AVS lateralization only at baseline (odds ratio, 8.93 [95% CI 3.00-26.32] versus both at baseline and after cosyntropin stimulation), and CT-AVS disagreement (odds ratio, 2.75 [95% CI, 1.20-6.31]).

CONCLUSIONS

Multifocal, asymmetrical bilateral PA is relatively common, and it cannot be excluded by robust AVS lateralization. Long-term postoperative monitoring should be routinely pursued, to identify residual PA and afford timely initiation of targeted medical therapy.

Sex-specific association of low-renin hypertension with metabolic and musculoskeletal health in Korean older adults

Introduction

Low-renin hypertension (LRH) accounts for approximately one-third of patients with hypertension and are more prevalent in women and the older adult population. Previous study has found a link between the renin-angiotensin-aldosterone system (RAAS) and sex hormones. However, there are insufficient data on the relationship between LRH and metabolic or musculoskeletal outcomes in older adults.

Methods and materials

Among the 343 participants from a population-based cohort study conducted between May 2018 and August 2019, a total of 256 (86 men older than 50 years and 170 postmenopausal women) were included. The presence of LRH was defined as plasma renin activity (PRA) <1 ng/mL/h and systolic blood pressure (BP) ≥130 or diastolic BP ≥80 mmHg based on the 2017 ACC/AHA guidelines. Individuals with missing data, and those who had used medications that could affect PRA within the past six months were excluded. Bone mineral density (BMD), trabecular bone score (TBS), and appendicular lean mass (ALM) index were assessed using dual-energy X-ray absorptiometry; degraded TBS was defined as partially degraded to degraded levels (≤1.350). Muscle function was assessed according to the Asian Working Group for Sarcopenia guidelines. PRA was measured using radioimmunoassay.

Results

The median age was 66 [61-72] years, and the body mass index (BMI) was 24.7 [23.0-26.4] kg/m2. Individuals with LRH, accounting for 34.8%, had lower diabetes mellitus; more dyslipidemia; and poorer muscle function, BMD, and TBS than those in the non-LRH group. In addition, PRA was positively correlated with C-peptide, HOMA-IR, TBS, and ALM index. After adjusting for covariates including age and BMI, LRH was negatively associated with femur neck T-score (adjusted β = -0.30, 95% CI [-0.55 to -0.05], p = 0.021) and the presence of LRH was significantly associated with degraded TBS in women (adjusted odds ratio = 3.00, 95% CI [1.36-6.58], p = 0.006).

Conclusion

Our findings suggest that LRH can influence clinical features and metabolic risk in older adults. Notably, LRH in postmenopausal women was linked to lower femur neck T-scores and degraded TBS, indicating sex-specific effects of LRH on bone health. Larger prospective studies are required to elucidate how changes in the RAAS affect metabolic and musculoskeletal outcomes in older adults.

The Mineralocorticoid Receptor in the Vasculature: Friend or Foe?

Originally described as the renal aldosterone receptor that regulates sodium homeostasis, it is now clear that mineralocorticoid receptors (MRs) are widely expressed, including in vascular endothelial and smooth muscle cells. Ample data demonstrate that endothelial and smooth muscle cell MRs contribute to cardiovascular disease in response to risk factors (aging, obesity, hypertension, atherosclerosis) by inducing vasoconstriction, vascular remodeling, inflammation, and oxidative stress. Extrapolating from its role in disease, evidence supports beneficial roles of vascular MRs in the context of hypotension by promoting inflammation, wound healing, and vasoconstriction to enhance survival from bleeding or sepsis. Advances in understanding how vascular MRs become activated are also reviewed, describing transcriptional, ligand-dependent, and ligand-independent mechanisms. By synthesizing evidence describing how vascular MRs convert cardiovascular risk factors into disease (the vascular MR as a foe), we postulate that the teleological role of the MR is to coordinate responses to hypotension (the MR as a friend).

Long-Term Follow-Up of Patients With Elevated Aldosterone-to-Renin Ratio but Negative Confirmatory Test: The Progression of Primary Aldosteronism Phenotypes

BACKGROUND

About 10% of patients with arterial hypertension have a positive screening test for primary aldosteronism (PA) and 50% to 70% of them have a negative confirmatory test: the appropriate follow-up of these patients is currently unknown. We investigated the incidence of PA in patients with previous negative confirmatory testing, after at least a 2-year follow-up.

METHODS

One hundred eighty-four patients with a previously elevated aldosterone-to-renin ratio followed by a negative confirmatory test were recruited in 2 hypertension centers (Torino and Munich). We repeated the screening test for PA and, if positive, the confirmatory test (seated saline infusion test or captopril challenge test). Primary end point of the study was the incidence of newly diagnosed overt PA, as defined by a positive confirmatory test.

RESULTS

After a mean follow-up of 5 years, 20% of patients developed overt PA. When subtype diagnosis was offered systematically, one-third of patients displayed unilateral PA. Patients who developed PA showed worsening of blood pressure control and a higher rate of cardiac organ damage, despite similar implementation of antihypertensive therapy, compared with patients without PA. A mild progression of autonomous aldosterone secretion was evident even in patients without confirmed PA but with relatively stable control of blood pressure levels over time.

CONCLUSIONS

About one-fifth of patients with a negative confirmatory test develop overt PA over time. A clinical follow-up of patients with a negative confirmatory test is advisable, along with the repetition of PA investigation, primarily in patients with worsening of blood pressure control.

Biomarkers to Guide Medical Therapy in Primary Aldosteronism

Primary aldosteronism (PA) is an endocrinopathy characterized by dysregulated aldosterone production that occurs despite suppression of renin and angiotensin II, and that is non-suppressible by volume and sodium loading. The effectiveness of surgical adrenalectomy for patients with lateralizing PA is characterized by the attenuation of excess aldosterone production leading to blood pressure reduction, correction of hypokalemia, and increases in renin-biomarkers that collectively indicate a reversal of PA pathophysiology and restoration of normal physiology. Even though the vast majority of patients with PA will ultimately be treated medically rather than surgically, there is a lack of guidance on how to optimize medical therapy and on key metrics of success. Herein, we review the evidence justifying approaches to medical management of PA and biomarkers that reflect endocrine principles of restoring normal physiology. We review the current arsenal of medical therapies, including dietary sodium restriction, steroidal and nonsteroidal mineralocorticoid receptor antagonists, epithelial sodium channel inhibitors, and aldosterone synthase inhibitors. It is crucial that clinicians recognize that multimodal medical treatment for PA can be highly effective at reducing the risk for adverse cardiovascular and kidney outcomes when titrated with intention. The key biomarkers reflective of optimized medical therapy are unsurprisingly similar to the physiologic expectations following surgical adrenalectomy: control of blood pressure with the fewest number of antihypertensive agents, normalization of serum potassium without supplementation, and a rise in renin. Pragmatic approaches to achieve these objectives while mitigating adverse effects are reviewed.

Diagnosis and management of primary hyperaldosteronism in patients with hypertension: a practical approach endorsed by the British and Irish Hypertension Society

Alongside the lack of homogeneity among international guidelines and consensus documents on primary hyperaldosteronism, the National UK guidelines on hypertension do not provide extensive recommendations regarding the diagnosis and management of this condition. Local guidelines vary from area to area, and this is reflected in the current clinical practice in the UK. In an attempt to provide support to the clinicians involved in the screening of subjects with hypertension and clinical management of suspected cases of primary hyperaldosteronism the following document has been prepared on the behalf of the BIHS Guidelines and Information Service Standing Committee. Through remote video conferences, the authors of this document reviewed an initial draft which was then circulated among the BIHS Executive members for feedback. A survey among members of the BIHS was carried out in 2022 to assess screening strategies and clinical management of primary hyperaldosteronism in the different regions of the UK. Feedback and results of the survey were then discussed and incorporated in the final document which was approved by the panel after consensus was achieved considering critical review of existing literature and expert opinions. Grading of recommendations was not performed in light of the limited available data from properly designed randomized controlled trials.

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.

Primary aldosteronism: molecular medicine meets public health

Primary aldosteronism is the most common single cause of hypertension and is potentially curable when only one adrenal gland is the culprit. The importance of primary aldosteronism to public health derives from its high prevalence but huge under-diagnosis (estimated to be <1% of all affected individuals), despite the consequences of poor blood pressure control by conventional therapy and enhanced cardiovascular risk. This state of affairs is attributable to the fact that the tools used for diagnosis or treatment are still those that originated in the 1970-1990s. Conversely, molecular discoveries have transformed our understanding of adrenal physiology and pathology. Many molecules and processes associated with constant adrenocortical renewal and interzonal metamorphosis also feature in aldosterone-producing adenomas and aldosterone-producing micronodules. The adrenal gland has one of the most significant rates of non-silent somatic mutations, with frequent selection of those driving autonomous aldosterone production, and distinct clinical presentations and outcomes for most genotypes. The disappearance of aldosterone synthesis and cells from most of the adult human zona glomerulosa is the likely driver of the mutational success that causes aldosterone-producing adenomas, but insights into the pathways that lead to constitutive aldosterone production and cell survival may open up opportunities for novel therapies.

In Situ Spatial Reconstruction of Distinct Normal and Pathological Cell Populations Within the Human Adrenal Gland

The human adrenal gland consists of concentrically organized, functionally distinct regions responsible for hormone production. Dysregulation of adrenocortical cell differentiation alters the proportion and organization of the functional zones of the adrenal cortex leading to disease. Current models of adrenocortical cell differentiation are based on mouse studies, but there are known organizational and functional differences between human and mouse adrenal glands. This study aimed to investigate the centripetal differentiation model in the human adrenal cortex and characterize aldosterone-producing micronodules (APMs) to better understand adrenal diseases such as primary aldosteronism. We applied spatially resolved in situ transcriptomics to human adrenal tissue sections from 2 individuals and identified distinct cell populations and their positional relationships. The results supported the centripetal differentiation model in humans, with cells progressing from the outer capsule to the zona glomerulosa, zona fasciculata, and zona reticularis. Additionally, we characterized 2 APMs in a 72-year-old woman. Comparison with earlier APM transcriptomes indicated a subset of core genes, but also heterogeneity between APMs. The findings contribute to our understanding of normal and pathological cellular differentiation in the human adrenal cortex.

Structure of rosettes in the zona glomerulosa of human adrenal cortex

Recent studies in mouse models have demonstrated that the multi-cellular rosette structure of the adrenal zona glomerulosa (ZG) is crucial for aldosterone production by ZG cells. However, the rosette structure of human ZG has remained unclear. The human adrenal cortex undergoes remodeling during aging, and one surprising change is the occurrence of aldosterone-producing cell clusters (APCCs). It is intriguing to know whether APCCs form a rosette structure like normal ZG cells. In this study, we investigated the rosette structure of ZG in human adrenal with and without APCCs, as well as the structure of APCCs. We found that glomeruli in human adrenal are enclosed by a laminin subunit β1 (lamb1)-rich basement membrane. In slices without APCCs, each glomerulus contains an average of 11 ± 1 cells. In slices with APCCs, each glomerulus in normal ZG contains around 10 ± 1 cells, while each glomerulus in APCCs has significantly more cells (average of 22 ± 1). Similar to what was observed in mice, cells in normal ZG or in APCCs of human adrenal formed rosettes through β-catenin- and F-actin-rich adherens junctions. The cells in APCCs form larger rosettes through enhanced adherens junctions. This study provides, for the first time, a detailed characterization of the rosette structure of human adrenal ZG and shows that APCCs are not an unstructured cluster of ZG cells. This suggests that the multi-cellular rosette structure may also be necessary for aldosterone production in APCCs.

Age-related Changes in the Adrenal Cortex: Insights and Implications

Aging is characterized by a gradual decline in physiological function. This process affects all organs including the adrenal cortex, which normally functions to produce essential steroid hormones including mineralocorticoids, glucocorticoids, and androgens. With increasing age, features such as reduced adrenal cortex size, altered zonation, and increased myeloid immune cell infiltration substantially alter the structure and function of the adrenal cortex. Many of these hallmark features of adrenal cortex aging occur both in males and females, yet are more enhanced in males. Hormonally, a substantial reduction in adrenal androgens is a key feature of aging, which is accompanied by modest changes in aldosterone and cortisol. These hormonal changes are associated with various pathological consequences including impaired immune responses, decreased bone health, and accelerated age-related diseases. One of the most notable changes with adrenal aging is the increased incidence of adrenal tumors, which is sex dimorphic with a higher prevalence in females. Increased adrenal tumorigenesis with age is likely driven by both an increase in genetic mutations as well as remodeling of the tissue microenvironment. Novel antiaging strategies offer a promising avenue to mitigate adrenal aging and alleviate age-associated pathologies, including adrenal tumors.

Hormones and Aging: An Endocrine Society Scientific Statement

Multiple changes occur across various endocrine systems as an individual ages. The understanding of the factors that cause age-related changes and how they should be managed clinically is evolving. This statement reviews the current state of research in the growth hormone, adrenal, ovarian, testicular, and thyroid axes, as well as in osteoporosis, vitamin D deficiency, type 2 diabetes, and water metabolism, with a specific focus on older individuals. Each section describes the natural history and observational data in older individuals, available therapies, clinical trial data on efficacy and safety in older individuals, key points, and scientific gaps. The goal of this statement is to inform future research that refines prevention and treatment strategies in age-associated endocrine conditions, with the goal of improving the health of older individuals.

The effect of age, sex and BMI on the aldosterone-to-renin ratio in essential hypertensive individuals

OBJECTIVE

The aldosterone-to-renin ratio (ARR) is widely used as a screening test for primary aldosteronism, but its determinants in patients with essential hypertension are not fully known. The purpose of the present investigation is to identify the impact of age, sex and BMI on renin, aldosterone and the ARR when measured under strict, standardized conditions in hypertensive patients without primary aldosteronism.

METHODS

We analysed the data of 423 consecutive hypertensive patients with no concomitant cardiac or renal disorders from two different hospitals (Rotterdam and Maastricht) who had been referred for evaluation of their hypertension. Those who were diagnosed with secondary causes of hypertension, including primary aldosteronism, were excluded from analysis. Patients who used oral contraceptives or had hormonal replacement therapy were excluded as well. Plasma aldosterone concentration (PAC), active plasma renin concentration (APRC) and the ARR were measured under standardized conditions. All measurements were taken in the supine position at 10.00 h in the morning, with one subgroup of patients adhering to a sodium-restricted diet (55 mmol/day) for no less than 3 weeks, and the other subgroup maintaining an ad libitum diet. In those who were receiving antihypertensive treatment, all medications were discontinued at least 3 weeks before testing.

RESULTS

In neither group did aldosterone correlate with age. Renin, however, was inversely related to age both during low-salt diet ( P  < 0.001) and during ad lib salt intake ( P  = 0.05). This resulted in a significant positive correlation between age and the ARR in both groups. Although on both dietary regimens, PAC and APRC were significantly higher in men when compared with women, the ARR was not significantly different between the two sexes. The age-relationships of renin and the ARR were comparable in men and women on both diets, albeit with greater variability in women. There was an upward trend between BMI and the ARR, which reached statistical significance only in men on low-salt diet. In multivariable regression analysis, age remained the only independent determinant of the ARR.

CONCLUSION

In our essential hypertensive population, the ARR increased significantly with age but was not affected by sex or BMI.

Skin-specific mechanisms of body fluid regulation in hypertension

Increasing evidence suggests excess skin Na+ accumulation in hypertension; however, the role of skin-specific mechanisms of local Na+/water regulation remains unclear. We investigated the association between measures of sweat and trans-epidermal water loss (TEWL) with Na+ content in the skin ([Na+]skin) and clinical characteristics in consecutive hypertensive patients. We obtained an iontophoretic pilocarpine-induced sweat sample, a skin punch biopsy for chemical analysis, and measures of TEWL from the upper limbs. Serum vascular endothelial growth factor-c (VEGF-c) and a reflectance measure of haemoglobin skin content served as surrogates of skin microvasculature. In our cohort (n = 90; age 21-86 years; females = 49%), sweat composition was independent of sex and BMI. Sweat Na+ concentration ([Na+]sweat) inversely correlated with [K+]sweat and was higher in patients on ACEIs/ARBs (P < 0.05). A positive association was found between [Na+]sweat and [Na+]skin, independent of sex, BMI, estimated Na+ intake and use of ACEi/ARBs (Padjusted = 0.025); both closely correlated with age (P < 0.01). Office DBP, but not SBP, inversely correlated with [Na+]sweat independent of other confounders (Padjusted = 0.03). Total sweat volume and Na+ loss were lower in patients with uncontrolled office BP (Padjusted < 0.005 for both); sweat volume also positively correlated with serum VEGF-c and TEWL. Lower TEWL was paralleled by lower skin haemoglobin content, which increased less after vasodilatory pilocarpine stimulation when BMI was higher (P = 0.010). In conclusion, measures of Na+ and water handling/regulation in the skin were associated with relevant clinical characteristics, systemic Na+ status and blood pressure values, suggesting a potential role of the skin in body-fluid homeostasis and therapeutic targeting of hypertension.

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.

Antihypertensive Effects of Esaxerenone in Older Patients with Primary Aldosteronism

Design

Retrospective cohort study. Patients. The data was obtained from a total of 87 PA patients treated with esaxerenone. The treatment group comprised 33 patients who received esaxerenone as first-line therapy and 54 patients that switched from another MRA to esaxerenone. Measurements. Blood pressure (BP), plasma aldosterone concentration (PAC), plasma renin activity (PRA), serum potassium level, estimated glomerular filtration rate (eGFR), urinary albumin-creatinine ratio (UACR), and brain natriuretic peptide (BNP) were assessed before and after treatment with esaxerenone. Patients with overall reductions in their systolic or diastolic BP by 10 mmHg, or more, were considered responders. Unpaired t-tests of the biochemical and personal parameters between responders and nonresponders were run to find the most influencing characteristic for treatment success.

Results

BP overall decreased after treatment with esaxerenone (systolic BP: P=0.025, diastolic BP: P=0.096). Serum potassium levels increased, while eGFR decreased (P=0.047 and 0.043, respectively). No patients needed a dose reduction or treatment discontinuation of esaxerenone based on the serum potassium and eGFR criteria. UACR and BNP decreased insignificantly. The responders were significantly older than the nonresponders of the esaxerenone treatment (P=0.0035).

Conclusions

Esaxerenone was effective in older patients with primary aldosteronism.

Ectopic localization of CYP11B1 and CYP11B2-expressing cells in the normal human adrenal gland

The sharp line of demarcation between zona glomerulosa (ZG) and zona fasciculata (ZF) has been recently challenged suggesting that this interface is no longer a compartment boundary. We have used immunohistochemical analyses to study the steroid 11β-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) pattern of expression and investigate the remodeling of the adrenal cortex in relation to aging. We analyzed human adrenal glands prepared from 47 kidney donors. No aldosterone-producing micronodules (APMs) were detectable in the younger donors aged between 22-39 but the functional ZG depicted by positive CYP11B2 staining demonstrated a lack of continuity. In contrast, the development of APMs was found in samples from individuals aged 40-70. Importantly, the progressive replacement of CYP11B2-expressing cells in the histological ZG by CYP11B1-expressing cells highlights the remodeling capacity of the adrenal cortex. In 70% of our samples, immunofluorescence studies revealed the presence of isolated or clusters of CYP11B2 positive cells in the ZF and zona reticularis. Our data emphasize that mineralocorticoid- and glucocorticoid-producing cells are distributed throughout the cortex and the medulla making the determination of the functional status of a cell or group of cells a unique tool in deciphering the changes occurring in adrenal gland particularly during aging. They also suggest that, in humans, steroidogenic cell phenotype defined by function is a stable feature and thus, the functional zonation might be not solely maintained by cell lineage conversion/migration.

Primary Aldosteronism: State-of-the-Art Review

We are witnessing a revolution in our understanding of primary aldosteronism (PA). In the past 2 decades, we have learned that PA is a highly prevalent syndrome that is largely attributable to pathogenic somatic mutations, that contributes to cardiovascular, metabolic, and kidney disease, and that when recognized, can be adequately treated with widely available mineralocorticoid receptor antagonists and/or surgical adrenalectomy. Unfortunately, PA is rarely diagnosed, or adequately treated, mainly because of a lack of awareness and education. Most clinicians still possess an outdated understanding of PA; from primary care physicians to hypertension specialists, there is an urgent need to redefine and reintroduce PA to clinicians with a modern and practical approach. In this state-of-the-art review, we provide readers with the most updated knowledge on the pathogenesis, prevalence, diagnosis, and treatment of PA. In particular, we underscore the public health importance of promptly recognizing and treating PA and provide pragmatic solutions to modify clinical practices to achieve this.

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.

Primary aldosteronism - a multidimensional syndrome

Primary aldosteronism is a common cause of hypertension and is a risk factor for cardiovascular and renal morbidity and mortality, via mechanisms mediated by both hypertension and direct insults to target organs. Despite its high prevalence and associated complications, primary aldosteronism remains largely under-recognized, with less than 2% of people in at-risk populations ever tested. Fundamental progress made over the past decade has transformed our understanding of the pathogenesis of primary aldosteronism and of its clinical phenotypes. The dichotomous paradigm of primary aldosteronism diagnosis and subtyping is being redefined into a multidimensional spectrum of disease, which spans subclinical stages to florid primary aldosteronism, and from single-focal or multifocal to diffuse aldosterone-producing areas, which can affect one or both adrenal glands. This Review discusses how redefining the primary aldosteronism syndrome as a multidimensional spectrum will affect the approach to the diagnosis and subtyping of primary aldosteronism.

Chinese normotensive and essential hypertensive reference intervals for plasma aldosterone and renin activity by liquid chromatography-tandem mass spectrometry

OBJECTIVES

The renin-angiotensin-aldosterone system (RAAS) regulates blood pressure. Plasma renin activities (PRA) and plasma aldosterone concentrations (PAC) are biomarkers related to RAAS. Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based measurements for PRA and PAC have become popular. Method-specific reference intervals (RIs) are required.

METHODS

Routine PRA and PAC services in a Hong Kong teaching hospital were based on LC-MS/MS methods. PRA and PAC RIs were developed for normotensive subjects and essential hypertensive (EH) patients. Healthy volunteers were recruited to establish normotensive RIs. PRA and PAC results of hypertensive patients with urine aldosterone tests for primary aldosteronism (PA) screening were retrieved from the laboratory information system. Patients without PA were included. Patients with secondary hypertension and patients on medications affecting the RAAS were excluded. The central 95% RIs were established based on the recommendations of the Clinical and Laboratory Standards Institute guideline C28-A3.

RESULTS

PRA and PAC of 170 normotensive volunteers and 362 EH patients were analysed. There was no sex-specific difference in PRA and PAC for normotensive and EH reference subjects. Differences for PRA and PAC were noted between normotensive subjects aged below 45 and their older counterparts. However, such a difference was only identified for PRA but not PAC in EH patients. Age-specific RIs were established accordingly.

CONCLUSIONS

This study presented age-specific LC-MS/MS RIs of PRA and PAC for both normotensive and EH populations for local Chinese in Hong Kong.

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.

Pathophysiology of bilateral hyperaldosteronism

PURPOSE OF REVIEW

Renin-independent aldosterone production from one or both affected adrenal(s), a condition known as primary aldosteronism (PA), is a common cause of secondary hypertension. In this review, we aimed to summarize recent findings regarding pathophysiology of bilateral forms of PA, including sporadic bilateral hyperaldosteronism (BHA) and rare familial hyperaldosteronism.

RECENT FINDINGS

The presence of subcapsular aldosterone synthase (CYP11B2)-expressing aldosterone-producing micronodules, also called aldosterone-producing cell clusters, appears to be a common histologic feature of adrenals with sporadic BHA. Aldosterone-producing micronodules frequently harbor aldosterone-driver somatic mutations. Other potential factors leading to sporadic BHA include rare disease-predisposing germline variants, circulating angiotensin II type 1 receptor autoantibodies, and paracrine activation of aldosterone production by adrenal mast cells. The application of whole exome sequencing has also identified new genes that cause inherited familial forms of PA.

SUMMARY

Research over the past 10 years has significantly improved our understanding of the molecular pathogenesis of bilateral PA. Based on the improved understanding of BHA, future studies should have the ability to develop more personalized treatment options and advanced diagnostic tools for patients with PA.

Differences in the presentation and evolution of primary aldosteronism in elderly (≥65 years) and young patients (<65 years)

OBJECTIVE

To compare the presentation and evolution of primary aldosteronism (PA) in the elderly (≥65 years) and young patients (<65 years).

METHODS

A retrospective multicenter study was performed in 20 Spanish hospitals of PA patients in follow-up between 2018 and 2021.

RESULTS

Three hundred fifty-two patients with PA <65 years and 88 patients ≥65 years were included. Older PA patients had a two-fold higher prevalence of type 2 diabetes, dyslipidemia, and cerebrovascular disease, but these differences disappeared after adjusting for hypertension duration. At diagnosis, diastolic blood pressure was lower than in young patients (83.3 ± 11.54 vs 91.6 ± 14.46 mmHg, P < 0.0001). No differences in the rate of overall correct cannulation (56.5% vs 42.3%, P = 0.206) or the diagnosis of unilaterality (76.9% vs 62.5%, P = 0.325) in the adrenal venous sampling (AVS) was observed between the elderly and young groups. However, there was a lower proportion of PA patients who underwent adrenalectomy in the elderly group than in the younger group (22.7% (n = 20) vs 37.5% (n = 132), P = 0.009). Nevertheless, no differences in the rate of postsurgical biochemical (100% (n = 14) vs 92.8% (n = 90), P = 0.299) and hypertension cure (38.6% (n = 51) vs 25.0% (n = 5), P = 0.239) were observed between both groups.

CONCLUSION

Older patients with PA have a worse cardiometabolic profile than young patients with PA that it is related to a longer duration of hypertension. However, the results of the AVS, and adrenalectomy are similar in both groups. Therefore, the management of elderly patients with PA should be based not only on age, but rather on the overall medical, physical, social, and mental characteristics of the patients.

Hypomethylation associated vitamin D receptor expression in ATP1A1 mutant aldosterone-producing adenoma

DNA methylation alteration is tissue-specific and play a pivotal role in regulating gene transcription during cell proliferation and survival. We aimed to detect genes regulated by DNA methylation, and then investigated whether the gene influenced cell proliferation or survival in adrenal cells. DNA methylation and qPCR analyses were performed in nonfunctioning adrenocortical adenoma (NFA, n = 12) and aldosterone-producing adenoma (APA, n = 35) samples. The VDR gene promoter was markedly hypomethylated in APA with ATP1A1 mutation, and the promoter methylation levels showed a significant inverse association with the transcripts in APA. ATP1A1 mutation led to VDR transcription in HAC15 cells, and VDR suppression abrogated ATP1A1 mutation-mediated cell proliferation in HAC15 cells. We demonstrated that APA with ATP1A1 mutation showed entire hypomethylation in the VDR promoter and abundant VDR mRNA and protein expression. VDR suppression abrogated ATP1A1 mutation-mediated cell proliferation in HAC15 cells. Abundant VDR expression would be essential for ATP1A1 mutation-mediated cell proliferation.

Salt Sensitivity of Blood Pressure and Aldosterone: Interaction Between the Lysine-specific Demethylase 1 Gene, Sex, and Age

CONTEXT

Salt sensitivity of blood pressure (SSBP) is associated with increased cardiovascular risk, especially in individuals of African descent, although the underlying mechanisms remain obscure. Lysine-specific demethylase 1 (LSD1) is a salt-sensitive epigenetic regulator associated with SSBP and aldosterone dysfunction. An LSD1 risk allele in humans is associated with SSBP and lower aldosterone levels in hypertensive individuals of African but not European descent. Heterozygous knockout LSD1 mice display SSBP and aldosterone dysregulation, but this effect is modified by age and biological sex. This might explain differences in cardiovascular risk with aging and biological sex in humans.

OBJECTIVE

This work aims to determine if LSD1 risk allele (rs587618) carriers of African descent display a sex-by-age interaction with SSBP and aldosterone regulation.

METHODS

We analyzed 297 individuals of African and European descent from the HyperPATH cohort. We performed multiple regression analyses for outcome variables related to SSBP and aldosterone.

RESULTS

LSD1 risk allele carriers of African (but not European) descent had greater SSBP than nonrisk homozygotes. Female LSD1 risk allele carriers of African descent had greater SSBP, mainly relationship-driven by women with low estrogen (postmenopausal). There was a statistically significant LSD1 genotype-sex interaction in aldosterone response to angiotensin II stimulation in individuals aged 50 years or younger, with female carriers displaying decreased aldosterone responsiveness.

CONCLUSION

SSBP associated with LSD1 risk allele status is driven by women with a depleted estrogen state. Mechanisms related to a resistance to develop SSBP in females are uncertain but may relate to an estrogen-modulating effect on mineralocorticoid receptor (MR) activation and/or LSD1 epigenetic regulation of the MR.