Double CYP11B1/CYP11B2 Immunohistochemistry and Detection of KCNJ5 Mutations in Primary Aldosteronism.

CONTEXT: The search for somatic mutations in adrenals resected from primary aldosteronism (PA) patients is being performed by Sanger sequencing, often implemented with immunohistochemistry (IHC)-guidance focused on aldosterone-producing (CYP11B2-positive) areas. OBJECTIVE: To investigate the impact of double IHC for CYP11B1 and CYP11B2 on Sanger and next generation sequencing (NGS). METHODS: We investigated 127 consecutive adrenal aldosterone producing adenoma from consenting surgically cured PA patients using double IHC for CYP11B1 and CYP11B2, Sanger sequencing and NGS. RESULTS: Double IHC for CYP11B2 and CYP11B1 revealed 3 distinct patterns: CYP11B2-positive adenoma (pattern 1), mixed CYP11B1/CYP11B2-positive adenoma (pattern 2), and adrenals with multiple small CYP11B2-positive nodules (pattern 3). Sanger sequencing allowed detection of KCNJ5 mutations in 44% of the adrenals; NGS revealed such mutations in 10% of those negative at Sanger and additional mutations in 61% of the cases. Importantly the rate of KCNJ5 mutations differed across patterns: 17.8% in pattern 1, 71.4% in pattern 2, and 10.7% in pattern 3 (χ2=22.492, p<0.001). CONCLUSIONS: NGS allowed detection of mutations in many adrenals that tested negative at Sanger sequencing. Moreover, the different distribution of KCNJ5 mutations across IHC patterns indicates that IHC-guided sequencing protocols selecting CYP11B2-positive areas could furnish results that might not be representative of the entire mutational status of the excised adrenal, which is important at a time when KCNJ5 mutations are suggested to drive management of APA patient.

Intracellular Calcium Dynamics in Primary Human Adrenocortical Cells Deciphered with a Novel Pipeline.

INTRODUCTION: The fluctuations of the intracellular Ca2+ concentration ([Ca2+]i) are key physiological signals for cell function under normal conditions and can undergo profound alterations in disease states, as high blood pressure due to endocrine disorders like primary aldosteronism (PA). However, when assessing such fluctuations several parameters in the Ca2+ signal dynamics need to be considered, which renders their assessment challenging. AIM: Aim to develop an observer-independent custom-made pipeline to analyze Ca2+ dynamics in terms of frequency and peak parameters, as amplitude, full width at half maximum (FWHM) and area under the curve (AUC). METHODS: We applied a custom-made methodology to aldosterone-producing adenoma (APA) and APA adjacent cells (AAC) and found this pipeline to be suitable for monitoring and processing a wide-range of [Ca2+]i events in these cell types delivering reproducible results. CONCLUSION: The designed pipeline can provide a useful tool for [Ca2+]i signal analysis that allows comparisons of Ca2+ dynamics not only in PA, but in other cell phenotypes that are relevant for the regulation of blood pressure.

'Essential' arterial hypertension: time for a paradigm change.

The exclusion of causes of hypertension is not systematically exploited in clinical practice. Therefore, essential hypertension is consistently presented as the most prevalent 'cause'. The paradox of a condition with unknown causes being described as a common cause of hypertension translates into a diagnosis of essential hypertension in most patients, which precludes the detection of a curable cause of hypertension. The aim of this review is to investigate how the notion of essential hypertension has developed and whether scientific evidence still support the notion of its high prevalence by examining the most recent studies. These studies provided solid scientific evidence that, when systematically sought for, secondary hypertension is quite common and that secondary hypertension is highly prevalent. The increased awareness should lead to a systematic search for, with the goal of curing or achieving a better control of high blood pressure, and ultimately improving patients' quality of life.

Subtype Identification of Surgically Curable Primary Aldosteronism During Treatment With Mineralocorticoid Receptor Blockade.

BACKGROUND: Current guidelines and consensus documents recommend withdrawal of mineralocorticoid receptor antagonists (MRAs) before primary aldosteronism (PA) subtyping by adrenal vein sampling (AVS), but this practice can cause severe hypokalemia and uncontrolled high blood pressure. Our aim was to investigate if unilateral PA can be identified by AVS during MRA treatment. METHODS: We compared the rate of unilateral PA identification between patients with and without MRA treatment in large data sets of patients submitted to AVS while off renin-angiotensin system blockers and ß-blockers. In sensitivity analyses, the between-group differences of lateralization index values after propensity score matching and the rate of unilateral PA identification in subgroups with undetectable (≤2 mUI/L), suppressed (<8.2 mUI/L), and unsuppressed (≥8.2 mUI/L) direct renin concentration levels were also evaluated. RESULTS: Plasma aldosterone concentration, direct renin concentration, and blood pressure values were similar in non-MRA-treated (n=779) and MRA-treated (n=61) patients with PA, but the latter required more antihypertensive agents (P=0.001) and showed a higher rate of adrenal nodules (82% versus 67%; P=0.022) and adrenalectomy (72% versus 54%; P=0.01). However, they exhibited no significant differences in commonly used AVS indices and the area under the receiving operating characteristic curve of lateralization index, both under unstimulated conditions and postcosyntropin. Several sensitivity analyses confirmed these results in propensity score matching adjusted models and in patients with undetectable, or suppressed or unsuppressed renin levels. CONCLUSIONS: At doses that controlled blood pressure and potassium levels, MRAs did not preclude the identification of unilateral PA at AVS. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01234220.

Tangram of Sodium and Fluid Balance.

Homeostasis of fluid and electrolytes is a tightly controlled physiological process. Failure of this process is a hallmark of hypertension, chronic kidney disease, heart failure, and other acute and chronic diseases. While the kidney remains the major player in the control of whole-body fluid and electrolyte homeostasis, recent discoveries point toward more peripheral mechanisms leading to sodium storage in tissues, such as skin and muscle, and a link between this sodium and a range of diseases, including the conditions above. In this review, we describe multiple facets of sodium and fluid balance from traditional concepts to novel discoveries. We examine the differences between acute disruption of sodium balance and the longer term adaptation in chronic disease, highlighting areas that cannot be explained by a kidney-centric model alone. The theoretical and methodological challenges of more recently proposed models are discussed. We acknowledge the different roles of extracellular and intracellular spaces and propose an integrated model that maintains fluid and electrolyte homeostasis and can be distilled into a few elemental players: the microvasculature, the interstitium, and tissue cells. Understanding their interplay will guide a more precise treatment of conditions characterized by sodium excess, for which primary aldosteronism is presented as a prototype.

Water and Electrolyte Content in Salt-Dependent HYpertension in the SKIn (WHYSKI): Effect of Surgical Cure of Primary Aldosteronism.

 INTRODUCTION: This study will test the hypothesis that primary aldosteronism (PA) involves alterations in Na+, K+, and water content in the skin that are corrected by adrenalectomy. AIM AND METHODS: In skin biopsies, we will measure the content of Na+, K+, water, by physical-chemical methods and the osmotic-stress-responsive transcription factor Tonicity-responsive Enhancer Binding Protein (TonEBP, NFAT5) mRNA copy number by droplet digital PCR, in sex-balanced cohorts of 18 -75-year-old consecutive consenting patients with unilateral and bilateral PA, primary (essential) hypertension, and normotension. Before surgery, the patients with unilateral PA will receive the mineralocorticoid receptor antagonist (MRA) canrenone at doses that correct hypokalemia and high blood pressure values. They will be reassessed in an identical way one month after surgical cure, while off MRA. PA patients not selected for adrenalectomy will similarly be assessed at diagnosis and follow-up while on stable MRA treatment. Since a pilot study showed a direct correlation of dry weight (DW) with skin electrolytes and water content and significant differences of biopsy DW between surgery and follow-up, meaningful comparison of the skin cations and water content and TonEBP mRNA copy number, between specimen obtained at different time points, will require DW- and total mRNA-adjustment, respectively. CONCLUSION: This study will provide novel information on the skin Na+, K+ and water content in PA, the paradigm of salt-dependent hypertension, and novel knowledge on the effect of surgical cure of hyperaldosteronism. The TonEBP-mediated regulation of Na+, K+ and water content in the skin will also be unveiled. TRAIL REGISTRY: Trial Registration number: NCT06090617. Date of Registration: 2023-10-19.

Total adrenalectomy versus subtotal adrenalectomy for bilateral pheochromocytoma: meta-analysis.

BACKGROUND: Bilateral pheochromocytomas are rare and often heritable. Total adrenalectomy leads to a definitive oncological cure, with subsequent definitive hypocortisolism. Subtotal adrenalectomy is a possible alternative. The aim of this study was to assess the effects of total adrenalectomy and subtotal adrenalectomy on bilateral pheochromocytoma in terms of post-surgical rate of recurrence, metastatic disease, and steroid dependence. METHODS: Systematic searches in the bibliographic databases PubMed, Embase, and Europe PMC were performed for 1945 to 1 June 2023. PRISMA guidelines were followed and the PICO strategy was applied to English-language studies comparing subtotal adrenalectomy with total adrenalectomy. A random-effects model was used to assess the different outcomes for studies with high heterogeneity. The Newcastle-Ottawa scale and the Risk Of Bias In Non-randomized Studies of Interventions ('ROBINS-I') tool were used to assess quality and risk of bias. RESULTS: From a total of 12 909 studies, 1202 patients (from 10 retrospective studies) were eligible for the meta-analysis. In six studies, including 1176 patients, the recurrence rate after subtotal adrenalectomy and total adrenalectomy was 14.1 versus 2.6 per cent respectively (OR 4.91, 95 per cent c.i. 1.30 to 18.54; P = 0.020; I2 72 per cent). In nine studies, including 1124 patients, the rate of post-surgical steroid dependence was 93.3 versus 11.6 per cent after total adrenalectomy and subtotal adrenalectomy respectively (OR 0.003, 95 per cent c.i. 0.0003 to 0.03; P < 0.00001; I2 66 per cent). Based on two studies, including 719 patients, no differences were evident regarding the occurrence of post-surgery metastatic disease. CONCLUSION: Subtotal adrenalectomy leads to less post-surgical primary adrenal insufficiency, but leads to a higher postoperative recurrence rate. Future prospective randomized studies, with clear eligibility criteria, are needed to confirm these results.

Coronary sinus diameter to estimate congestion and predict survival.

Background: Congestion predicts a poor prognosis, but its assessment is challenging in clinical practice and requires a multiparametric approach. We investigated if the coronary sinus (CS) diameter can predict mortality in a human model of rapid fluid unloading. Methods: We measured by echocardiography the CS, and the inferior vena cava (IVC) for comparison, in 60 patients with end-stage chronic kidney disease (ESKD) immediately before and after hemodialysis (HD; age 76 [57-81] years, 40% female, left ventricular ejection fraction 57 [53-56]%). Patients were prospectively followed up for all-cause mortality. Results: HD-induced decongestion decreased the maximum diameters of both CS and IVC (p ≤ 0.001 for all). The maximum diameter of the CS (CSmax) was as accurate as the IVC maximum diameter and collapsibility for the identification of congestion, defined as pre-hemodialysis status (AUROC CSmax = 0.902 vs IVC = 0.895, p = n.s.). A CSmax diameter after hemodialysis > 9 mm predicted all-cause mortality at 12 months (Log-rank Chi square = 11.49, p < 0.001). Conclusions: A persistently dilated CS after hemodialysis is a marker of residual congestion and predicts death at one year in high-risk ESKD patients.

Expression of functional mineralocorticoid receptor (MR) and G-protein coupled estrogen receptor (GPER) in human T lymphocytes.

Aldosterone plays a key role in controlling blood pressure (BP) values by maintaining body salt, water, and fluid homeostasis. Excess aldosterone production is associated with arterial hypertension, cardiovascular and metabolic diseases, partly via generation of an inflammatory state followed by fibrotic changes in the organs that are target of hypertension. Aldosterone exerts genomic effects that are known to involve activation of the mineralocorticoid receptor (MR). Other aldosterone effects, including those usually defined as 'rapid' or 'non genomic', involve additional receptors as the G-protein coupled estrogen receptor (GPER). To date, the receptor(s) implicated in the inflammatory action of aldosterone in cells of the innate and adaptive immunity are unknown. Considering the potential role of T-lymphocytes in adaptive immunity in arterial hypertension and related hypertension-mediated organ damage (HMOD), we herein investigated and quantified the expression of the MR and GPER in human CD4+ and CD8+ T-cells. Results provided compelling evidence for the presence at the mRNA and protein level and suggest a functional role of these receptors in the two T-lymphocyte subtypes, thus indicating that they can represent a potential target for modulation of steroid hormone-induced inflammation and ensuing HMOD.

RAndomized Clinical Trial Of NAfamostat Mesylate, A Potent Transmembrane Protease Serine 2 (TMPRSS2) Inhibitor, in Patients with COVID-19 Pneumonia.

Even though SARS-CoV-2 was declared by WHO as constituting no longer a public health emergency, the development of effective treatments against SARS-CoV-2 infection remains a critical issue to prevent complications, particularly in fragile patients. The protease inhibitor nafamostat, currently used in Japan and Korea for pancreatitis, owing to its anticoagulant properties for disseminated intravascular coagulation (DIC), is appealing for the treatment of COVID-19 infection, because it potently inhibits the transmembrane protease serine 2 (TMPRSS2) that, after virus binding to ACE-2, allows virus entry into the cells and replication. Moreover, it could prevent the DIC and pulmonary embolism frequently associated with COVID-19 infection. The goal of the RAndomized Clinical Trial Of NAfamostat (RACONA) study, designed as a prospective randomized, double-blind placebo-controlled clinical trial, was to investigate the efficacy and safety of nafamostat mesylate (0.10 mg/kg/h iv for 7 days), on top of the optimal treatment, in COVID-19 hospitalized patients. We could screen 131 patients, but due to the predefined strict inclusion and exclusion criteria, only 15 could be randomized to group 1 (n = 7) or group 2 (n = 8). The results of an ad interim safety analysis showed similar overall trends for variables evaluating renal function, coagulation, and inflammation. No adverse events, including hyperkalemia, were found to be associated with nafamostat. Thus, the RACONA study showed a good safety profile of nafamostat, suggesting that it could be usefully used in COVID-19 hospitalized patients.

Pickering Syndrome: An Overlooked Renovascular Cause of Recurrent Heart Failure.

ABSTRACTRecurring and rapidly developing (flash) pulmonary edema is the hallmark of Pickering syndrome, affecting patients with hypertension and atherosclerotic renal artery stenosis (either bilateral or unilateral) in a solitary functioning kidney, and impaired renal function. We herein report on a series of consecutive patients with recurrent hospital admissions for pulmonary edema, impaired renal function (chronic kidney disease class 4-5), and atherosclerotic bilateral renal artery stenosis, in whom Pickering syndrome had been long neglected. We also describe a streamlined diagnostic strategy entailing little or no need for contrast medium, thus carrying no risks of further worsening of renal function. This allowed us to make the correct diagnosis and opened the way to revascularization by percutaneous transluminal renal angioplasty with stent, which provided swift recovery of kidney function with resolution of pulmonary congestion and long-term pulmonary edema- and dialysis-free survival in all cases. In summary, these findings support the following key messages: (1) considering the diagnosis of Pickering syndrome, followed by searching atherosclerotic renal artery stenosis, is an essential step toward a life-saving revascularization that avoids dialysis and an otherwise poor outcome; and (2) a simplified strategy entailing little or no need for contrast medium, carrying no associated risks of deteriorating renal function, permits the diagnosis of Pickering syndrome.

Unilaterally Selective Adrenal Vein Sampling for Identification of Surgically Curable Primary Aldosteronism.

BACKGROUND: Adrenal venous sampling is recommended for the identification of unilateral surgically curable primary aldosteronism but is often clinically useless, owing to failed bilateral adrenal vein cannulation. OBJECTIVES: To investigate if only unilaterally selective adrenal vein sampling studies can allow the identification of the responsible adrenal. METHODS: Among 1625 patients consecutively submitted to adrenal vein sampling in tertiary referral centers, we selected those with selective adrenal vein sampling results in at least one side; we used surgically cured unilateral primary aldosteronism as gold reference. The accuracy of different values of the relative aldosterone secretion index (RASI), which estimates the amount of aldosterone produced in each adrenal gland corrected for catheterization selectivity, was examined. RESULTS: We found prominent differences in RASI values distribution between patients with and without unilateral primary aldosteronism. The diagnostic accuracy of RASI values estimated by the area under receiver operating characteristic curves was 0.714 and 0.855, respectively, in the responsible and the contralateral side; RASI values >2.55 and ≤0.96 on the former and the latter side furnished the highest accuracy for detection of surgically cured unilateral primary aldosteronism. Moreover, in the patients without unilateral primary aldosteronism, only 20% and 16% had RASI values ≤0.96 and >2.55. CONCLUSIONS: With the strength of a large real-life data set and use of the gold reference entailing an unambiguous diagnosis of unilateral primary aldosteronism, these results indicate the feasibility of identifying unilateral primary aldosteronism using unilaterally selective adrenal vein sampling results. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT01234220.

Aldosterone Biosynthesis Is Potently Stimulated by Perfluoroalkyl Acids: A Link between Common Environmental Pollutants and Arterial Hypertension.

The large environmental contamination of drinking water by perfluoroalkyl substances (PFAS) markedly increased the plasma levels of pentadecafluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in a Northern Italy population with a high prevalence of arterial hypertension and cardiovascular disease. As the link between PFAS and arterial hypertension is unknown, we investigated if they enhance the biosynthesis of the well-known pressor hormone aldosterone. We found that PFAS increased aldosterone synthase (CYP11B2) gene expression by three-fold and doubled aldosterone secretion and cell and mitochondria reactive oxygen species (ROS) production over controls (p < 0.01 for all) in human adrenocortical carcinoma cells HAC15. They also enhanced the effects of Ang II on CYP11B2 mRNA and aldosterone secretion (p < 0.01 for all). Moreover, when added 1 h before, the ROS scavenger tempol abolished the effect of PFAS on CYP11B2 gene expression. These results indicate that at concentrations mimicking those found in human plasma of exposed individuals, PFAS are potent disruptors of human adrenocortical cell function, and might act as causative factors of human arterial hypertension via increased aldosterone production.

Challenges in the evaluation of endothelial cell dysfunction: a statement from the European Society of Hypertension Working Group on Endothelin and Endothelial Factors.

Endothelial cell function is mediated by different mechanisms in different vascular beds. Moreover, in humans, endothelial cell dysfunction triggers and accelerates the progression of cardiovascular and chronic kidney diseases. Progression of such diseases can be in part mitigated by the control of cardiovascular risk factors and drugs targeting different systems, including endothelin receptor antagonists (ERAs), renin-angiotensin aldosterone antagonists and agents affecting glucose metabolism, all of which were shown to improve endothelial cell function. In recent years, the microRNAs, which are endogenous regulators of gene expression, have been identified as transmitters of information from endothelial cells to vascular smooth muscle cells, suggesting that they can entail tools to assess the endothelial cell dysfunction in arterial hypertension and target for pharmacologic intervention. This article critically reviews current challenges and limitations of available techniques for the invasive and noninvasive assessment of endothelial cell function, and also discusses therapeutic aspects as well as directions for future research in the areas of endothelial cell biology and pathophysiology in humans.

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.

Exclusion Tests in Unilateral Primary Aldosteronism (ExcluPA) Study.

CONTEXT: Determining the diagnostic accuracy of "exclusion" tests for primary aldosteronism (PA) compared to the aldosterone to renin ratio (ARR) is fundamental to avoid invasive subtyping in false-positive patients at screening. OBJECTIVE: To assess the accuracy of exclusion tests for PA using the diagnosis of unilateral PA as reference. METHODS: PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched for studies published from January 1, 1970, to December 31, 2021, meeting tight quality criteria. Data were extracted following the PRISMA methodology. We performed a two-stage meta-analysis that entailed an exploratory and a validation phase based on a "golden" or "gold" diagnostic standard, respectively. Pooled specificity, negative likelihood ratio, diagnostic odds ratio, and summary area under the ROC curve (sAUROC) were calculated to analyze the accuracy of exclusion tests. RESULTS: A meta-analysis of 31 datasets comprising a total of 4242 patients fulfilling the predefined inclusion criteria found that pooled accuracy estimates (sAUROC) did not differ between the ARR (0.95; 95% CI, 0.92-0.98), the captopril challenge test (CCT) (0.92; 95% CI, 0.88-0.97), and the saline infusion test (SIT) (0.96; 95% CI, 0.94-0.99). Solid information could not be obtained for the fludrocortisone suppression test and the furosemide upright test, which were assessed in only 1 study each. CONCLUSION: The apparently high diagnostic accuracy of the CCT and the SIT was due to the selection of patients with an elevated ARR and thus a high pretest probability of unilateral PA; however, neither test furnished a diagnostic gain over the ARR. Therefore, the systematic use of these exclusion tests in clinical practice is not justified by available evidence.

Increased Soluble Interleukin 6 Receptors in Fabry Disease.

Fabry disease (FD) is an X-linked lysosome storage disease that results in the accumulation of globotriaosylceramide (Gb3) throughout the body leading to irreversible target organ damage. As the role of secondary mediators (inflammatory molecules) and their mechanisms has not been fully elucidated, we focused on the interleukin (IL)-6 system in adult FD patients and in matched healthy subjects. To obtain insights into the complex regulation of IL-6 actions, we used a novel approach that integrates information from plasma and exosomes of FD patients (n = 20) and of healthy controls (n = 15). Soluble IL-6 receptor (sIL-6R) levels were measured in plasma with the ELISA method, and membrane-bound IL-6R was quantified in plasma and urinary exosomes using flow cytometry. In FD patients, the levels of soluble IL-6R in plasma were higher than in control subjects (28.0 ± 5.4 ng/mL vs. 18.9 ± 5.4 ng/mL, p < 0.0001); they were also higher in FD subjects with the classical form as compared to those with the late-onset form of the disease (36.0 ± 11.4 ng/mL vs. 26.1 ± 4.5 ng/mL, p < 0.0001). The percentage of urinary exosomes positive for IL-6R was slightly lower in FD (97 ± 1 vs. 100 ± 0% of events positive for IL-6R, p < 0.05); plasma IL-6 levels were not increased. These results suggest a potential role of IL-6 in triggering the inflammatory response in FD. As in FD patients only the levels of sIL-6Rs are consistently higher than in healthy controls, the IL-6 pathogenic signal seems to prevail over the homeostatic one, suggesting a potential mechanism causing multi-systemic damage in FD.

Whole blood methylome-derived features to discriminate endocrine hypertension.

BACKGROUND: Arterial hypertension represents a worldwide health burden and a major risk factor for cardiovascular morbidity and mortality. Hypertension can be primary (primary hypertension, PHT), or secondary to endocrine disorders (endocrine hypertension, EHT), such as Cushing's syndrome (CS), primary aldosteronism (PA), and pheochromocytoma/paraganglioma (PPGL). Diagnosis of EHT is currently based on hormone assays. Efficient detection remains challenging, but is crucial to properly orientate patients for diagnostic confirmation and specific treatment. More accurate biomarkers would help in the diagnostic pathway. We hypothesized that each type of endocrine hypertension could be associated with a specific blood DNA methylation signature, which could be used for disease discrimination. To identify such markers, we aimed at exploring the methylome profiles in a cohort of 255 patients with hypertension, either PHT (n = 42) or EHT (n = 213), and at identifying specific discriminating signatures using machine learning approaches. RESULTS: Unsupervised classification of samples showed discrimination of PHT from EHT. CS patients clustered separately from all other patients, whereas PA and PPGL showed an overall overlap. Global methylation was decreased in the CS group compared to PHT. Supervised comparison with PHT identified differentially methylated CpG sites for each type of endocrine hypertension, showing a diffuse genomic location. Among the most differentially methylated genes, FKBP5 was identified in the CS group. Using four different machine learning methods-Lasso (Least Absolute Shrinkage and Selection Operator), Logistic Regression, Random Forest, and Support Vector Machine-predictive models for each type of endocrine hypertension were built on training cohorts (80% of samples for each hypertension type) and estimated on validation cohorts (20% of samples for each hypertension type). Balanced accuracies ranged from 0.55 to 0.74 for predicting EHT, 0.85 to 0.95 for predicting CS, 0.66 to 0.88 for predicting PA, and 0.70 to 0.83 for predicting PPGL. CONCLUSIONS: The blood DNA methylome can discriminate endocrine hypertension, with methylation signatures for each type of endocrine disorder.