Prevalence of angiotensin II type 1 receptor (AT1R)-activating autoantibodies in primary aldosteronism.

Autoantibodies to the angiotensin II type 1 receptor (AT1R) have been reported in patients with primary aldosteronism, including aldosterone producing adenoma (APA) and idiopathic adrenal hyperplasia (IAH). Sera from 25 primary aldosteronism subjects (12 with IAH and 13 with APA) and 15 normotensive control subjects were assayed for AT1R autoantibodies by enzyme-linked immunosorbent assay and an AT1R-transfected cell-based bioassay. Nine of 12 IAH subjects (75%) and six of 13 APA subjects (46%) were positive for AT1R autoantibodies in the bioactivity assay. The mean AT1R autoantibody activity for the IAH and APA subjects was significantly greater than controls (P < .001 and P < .01, respectively), and this in vitro activity was suppressed by the AT1R blocker losartan. None of the controls had significant AT1R autoantibody activity. Enzyme-linked immunosorbent assay values were less sensitive but were positive in some subjects with IAH and APA. The mean arterial pressure of these primary aldosteronism subjects correlated modestly with AT1R autoantibody activity. These data confirm the presence of active AT1R autoantibodies in a high percentage of subjects with primary aldosteronism irrespective of their underlying etiology. These observations have both pathophysiological and clinical implications.

Genetic spectrum and clinical correlates of somatic mutations in aldosterone-producing adenoma.

Primary aldosteronism is the most common form of secondary hypertension. Somatic mutations in KCNJ5, ATP1A1, ATP2B3, and CACNA1D have been described in aldosterone-producing adenomas (APAs). Our aim was to investigate the prevalence of somatic mutations in these genes in unselected patients with APA (n=474), collected through the European Network for the Study of Adrenal Tumors. Correlations with clinical and biochemical parameters were first analyzed in a subset of 199 patients from a single center and then replicated in 2 additional centers. Somatic heterozygous KCNJ5 mutations were present in 38% (180/474) of APAs, whereas ATP1A1 mutations were found in 5.3% (25/474) and ATP2B3 mutations in 1.7% (8/474) of APAs. Previously reported somatic CACNA1D mutations as well as 10 novel CACNA1D mutations were identified in 44 of 474 (9.3%) APAs. There was no difference in the cellular composition of APAs or in CYP11B2, CYP11B1, KCNJ5, CACNA1D, or ATP1A1 gene expression in APAs across genotypes. Patients with KCNJ5 mutations were more frequently female, diagnosed younger, and with higher minimal plasma potassium concentrations compared with CACNA1D mutation carriers or noncarriers. CACNA1D mutations were associated with smaller adenomas. These associations were largely dependent on the population structure of the different centers. In conclusion, recurrent somatic mutations were identified in 54% of APAs. Young women with APAs are more likely to be KCNJ5 mutation carriers; identification of specific characteristics or surrogate biomarkers of mutation status may lead to targeted treatment options.

KCNJ5 gene somatic mutations affect cardiac remodelling but do not preclude cure of high blood pressure and regression of left ventricular hypertrophy in primary aldosteronism.

OBJECTIVE: Aldosterone exerts detrimental cardiovascular effects, and patients with an aldosterone-producing adenoma (APA) carrying somatic mutations in the KCNJ5 K(+) channel (mutAPA) have higher plasma aldosterone concentration than wild-type APA (wtAPA) patients. We therefore investigated whether mutAPA patients develop a more prominent cardiovascular damage than wtAPA patients. METHODS AND FINDINGS: From 257 consecutive primary aldosteronism patients, we identified 176 who had both a diagnosis of APA by the 'four corners' criteria and high-quality echocardiographic data. Of them, 129 with KCNJ5 sequencing information and long-term follow-up data were compared for echocardiographic changes according to presence (mutAPA, 26%) or absence (wtAPA, 74%) of the KCNJ5 mutations. At baseline, the mutAPA were similar to the wtAPA for blood pressure (BP) and need for antihypertensive medications. However, they had higher left ventricular mass index (59 ± 19 vs. 51 ± 13 g/h(2.7); P < 0.05) and plasma aldosterone concentration [49 (32-68) vs. 36 (25-52) ng/dl); P = 0.048] than the wtAPA patients. In spite of their more prominent cardiac involvement, the mutAPA patients exhibited a fall of BP and plasma aldosterone similar to wtAPA, and a regression of left ventricular mass index. CONCLUSIONS: Compared to the wild-type APA patients those with KCNJ5 mutations showed more prominent cardiovascular damage. Notwithstanding this, their chances of being cured from the hyperaldosteronism and the high BP, and of regression of left ventricular hypertrophy after adrenalectomy, were not compromised by the presence of these mutations.

The antiproliferative effects of ouabain and everolimus on adrenocortical tumor cells.

Ouabain is a cardiotonic steroid obtained from Strophanthus. Recently its role as antiproliferative agent has been investigated in tumor cells. Everolimus is a derivative of rapamycin and acts as a signal transduction inhibitor. Adrenocortical carcinoma is a rare cancer, with poor prognosis. This research focuses on antineoplastic properties of ouabain and its association with everolimus. We analyzed the effects of drugs on cells by MTT assay, by [(3)H] thymidine assay, by Wright's staining, by homogeneous caspases assay, by flow cytometry analysis and by Western blot analysis on H295R and SW13 cells and on primary adrenocortical tumor cells. Ouabain induced cell viability reduction in SW13, H295R and 5 primary adrenocortical tumor cells. Combination of ouabain with everolimus produced a stronger cytotoxic effect on cell proliferation and viability. Marked morphological changes were observed in both SW13 and H295R cell lines after ouabain treatment, with an increase in necrosis. Cell cycle distribution was altered by ouabain in SW13. Analysis of apoptosis demonstrated an increase in caspase activity, clearly evident for SW13 at 72h. FACS analysis by Annexin V-FITC kit and propidium iodide confirmed an increased level of necrosis at higher concentrations. Western blot analysis showed that PI3k/Akt signaling pathway was modified after ouabain treatments in SW13. Ouabain exerts antiproliferative effects on SW13 and H295R cell lines and on primary adrenocortical tumor cells. These data suggest that ouabain or ouabain derivatives may be potential anticancer agents.

Long-term control of arterial hypertension and regression of left ventricular hypertrophy with treatment of primary aldosteronism.

Primary aldosteronism (PA), a common cause of high blood pressure (BP), induces left ventricular (LV) hypertrophy and an excess rate of cardiovascular events. Whether its treatment provides long-term cure of hypertension and regression of cardiovascular damage remains uncertain. To the aim of assessing the effect of treatment of PA on BP and LV changes, we prospectively recruited 323 patients in a long-term follow-up study entailing serial echocardiography evaluations. Of them, 180 had PA and were assigned to either adrenalectomy (n=110) or medical therapy (n=70) on the basis of the adrenal vein sampling. The remaining 143 were consecutive optimally treated primary hypertensive patients. At baseline, the PA patients had more inappropriate LV mass than PH patients (27.1% versus 16.2%; P=0.020), despite similar BP values. At a median follow-up of 36 months (range, 6-225), BP was lowered (P<0.0001 versus baseline) to similar values in adrenalectomized (135±15/83±9 mm Hg), medically treated PA (133±11/83±7 mm Hg), and PH (139±15/86±9 mm Hg) patients. To this end, the adrenalectomized patients required significantly less drugs than the other groups. In PA patients, the LV mass index and the rate of LV hypertrophy fell through LV inward remodeling to the level of optimally treated PH patients, indicating that the LV work markedly decreased. Findings were similar when long-term (≥5 and ≥10 years) data were examined. Thus, an early diagnosis and a specific treatment of PA warrant normalization of BP and reversal of detrimental LV changes at long term.

Somatic mutations in the KCNJ5 gene raise the lateralization index: implications for the diagnosis of primary aldosteronism by adrenal vein sampling.

CONTEXT: Somatic mutations in the selectivity filter of KCNJ5 K(+) channel were found to be associated with higher plasma aldosterone concentrations in the patients with an aldosterone-producing adenoma (APA). OBJECTIVE: We investigated whether plasma aldosterone levels and the lateralization index are higher from the side with the APA with the mutation, as compared with those without the mutation. DESIGN: From 170 consecutive APA patients with comprehensive clinical and KCNJ5 data and a conclusive diagnosis, we recruited 91 patients with adrenal vein sampling and follow-up data. We measured CYP11B1 and CYP11B2 mRNA in APA tissue and plasma aldosterone (PAC) and plasma cortisol concentrations (PCC) in adrenal vein blood. To determine whether KCNJ5 mutations affected aldosterone output from the APA, we calculated the lateralization index (defined as the ratio of PAC to PCC at the APA side over the PAC to PCC ratio at the contralateral side). We also calculated two indexes of the aldosterone production from the APA side and the contralateral suppression index. RESULTS: The mRNA content of CYP11B2, but not of CYP11B1, and, accordingly, the lateralization index was higher (29.9 ± 7.4 vs. 10.3 ± 3.6, P < 0.02) in the APA with the mutation than in the APA without the mutation. CONCLUSIONS: APA patients with the somatic KCNJ5 mutations showed a higher production of aldosterone than those without such mutations, which translates in a higher lateralization index. Thus, they are more likely to be identified at adrenal vein sampling and therefore to receive adrenalectomy.

Combination of sorafenib and everolimus impacts therapeutically on adrenocortical tumor models.

Treatment options are insufficient in patients with adrenocortical carcinoma (ACC). Based on the efficacy of sorafenib, a tyrosine kinase inhibitor, and everolimus, an inhibitor of the mammalian target of rapamycin in tumors of different histotype, we aimed at testing these drugs in adrenocortical cancer models. The expression of vascular endothelial growth factor and its receptors (VEGFR1-2) was studied in 18 ACCs, 33 aldosterone-producing adenomas, 12 cortisol-producing adenomas, and six normal adrenal cortex by real-time PCR and immunohistochemistry and by immunoblotting in SW13 and H295R cancer cell lines. The effects of sorafenib and everolimus, alone or in combination, were tested on primary adrenocortical cultures and SW13 and H295R cells by evaluating cell viability and apoptosis in vitro and tumor growth inhibition of tumor cell line xenografts in immunodeficient mice in vivo. VEGF and VEGFR1-2 were detected in all samples and appeared over-expressed in two-thirds of ACC specimens. Dose-dependent inhibition of cell viability was observed particularly in SW13 cells after 24 h treatment with either drug; drug combination produced markedly synergistic growth inhibition. Increasing apoptosis was observed in tumor cells treated with the drugs, particularly with sorafenib. Finally, a significant mass reduction and increased survival were observed in SW13 xenograft model undergoing treatment with the drugs in combination. Our data suggest that an autocrine VEGF loop may exist within ACC. Furthermore, a combination of molecularly targeted agents may have both antiangiogenic and direct antitumor effects and thus could represent a new therapeutic tool for the treatment of ACC.

Effect of KCNJ5 mutations on gene expression in aldosterone-producing adenomas and adrenocortical cells.

CONTEXT: Primary aldosteronism is a heterogeneous disease that includes both sporadic and familial forms. A point mutation in the KCNJ5 gene is responsible for familial hyperaldosteronism type III. Somatic mutations in KCNJ5 also occur in sporadic aldosterone producing adenomas (APA). OBJECTIVE: The objective of the study was to define the effect of the KCNJ5 mutations on gene expression and aldosterone production using APA tissue and human adrenocortical cells. METHODS: A microarray analysis was used to compare the transcriptome profiles of female-derived APA samples with and without KCNJ5 mutations and HAC15 adrenal cells overexpressing either mutated or wild-type KCNJ5. Real-time PCR validated a set of differentially expressed genes. Immunohistochemical staining localized the KCNJ5 expression in normal adrenals and APA. RESULTS: We report a 38% (18 of 47) prevalence of KCNJ5 mutations in APA. KCNJ5 immunostaining was highest in the zona glomerulosa of NA and heterogeneous in APA tissue, and KCNJ5 mRNA was 4-fold higher in APA compared with normal adrenals (P < 0.05). APA with and without KCNJ5 mutations displayed slightly different gene expression patterns, notably the aldosterone synthase gene (CYP11B2) was more highly expressed in APA with KCNJ5 mutations. Overexpression of KCNJ5 mutations in HAC15 increased aldosterone production and altered expression of 36 genes by greater than 2.5-fold (P < 0.05). Real-time PCR confirmed increases in CYP11B2 and its transcriptional regulator, NR4A2. CONCLUSIONS: KCNJ5 mutations are prevalent in APA, and our data suggest that these mutations increase expression of CYP11B2 and NR4A2, thus increasing aldosterone production.

Prevalence, clinical, and molecular correlates of KCNJ5 mutations in primary aldosteronism.

Primary aldosteronism is the most common form of secondary hypertension. Mutations in the KCNJ5 gene have been described recently in aldosterone-producing adenomas (APAs). The aim of this study was to investigate the prevalence of KCNJ5 mutations in unselected patients with primary aldosteronism and their clinical, biological and molecular correlates. KCNJ5 sequencing was performed on somatic (APA, n=380) and peripheral (APA, n=344; bilateral adrenal hyperplasia, n=174) DNA of patients with primary aldosteronism, collected through the European Network for the Study of Adrenal Tumors. Transcriptome analysis was performed in 102 tumors. Somatic KCNJ5 mutations (p.Gly151Arg or p.Leu168Arg) were found in 34% (129 of 380) of APA. They were significantly more prevalent in females (49%) than males (19%; P<10(-3)) and in younger patients (42.1±1.0 versus 47.6±0.7 years; P<10(-3)) and were associated with higher preoperative aldosterone levels (455±26 versus 376±17 ng/L; P=0.012) but not with therapeutic outcome after surgery. Germline KCNJ5 mutations were found neither in patients with APA nor those with bilateral adrenal hyperplasia. Somatic KCNJ5 mutations were specific for APA, because they were not identified in 25 peritumoral adrenal tissues or 16 cortisol-producing adenomas. Hierarchical clustering of transcriptome profiles showed that APAs with p.Gly151Arg or p.Leu168Arg mutations were indistinguishable from tumors without KCNJ5 mutations. In conclusion, although a large proportion of sporadic APAs harbors somatic KCNJ5 mutations, germline mutations are not similarly causative for bilateral adrenal hyperplasia. KCNJ5 mutation carriers are more likely to be females; younger age and higher aldosterone levels at diagnosis suggest that KCNJ5 mutations may be associated with a more florid phenotype of primary aldosteronism.

Primary aldosteronism: what consensus for the diagnosis.

Primary Aldosteronism (PA) is characterized by inappropriate aldosterone production partially autonomous of the renin-angiotensin system. Since the ARR ratio was introduced a much higher prevalence of this disease is recognized. PA could be the most common identifiable, specifically treatable and potentially curable form of hypertension so the need of a clinical practice guideline on primary aldosteronism becomes mandatory. Recently the Endocrine Society USA published clinical practice guidelines for the diagnosis and treatment of patients with primary hyperaldosteronism. Systematic reviews of available evidence were used to formulate the key treatment and prevention recommendations. Actually the Endocrine Society consensus is the most used guidelines in diagnosis and treatment of hyperaldosteronism. However, there remains a few unresolved issues, which unfortunately require more of a detour guide and cannot be easily addressed by a straight forward guideline.

Hypertension in Cushing's syndrome: from pathogenesis to treatment.

Hypertension is one of the most distinguishing features of endogenous Cushing's syndrome (CS), as it is present in about 80% of adult patients whereas in children its prevalence is about 47%. Hypertension in CS is significantly correlated with the duration of hypercortisolism and results from the interplay between several pathophysiological mechanisms regulating plasma volume, peripheral vascular resistance and cardiac output, all of which are increased in this state. Glucocorticoids cause hypertension through several mechanisms: their intrinsic mineralocorticoid activity; through activation of the renin-angiotensin system; by enhancement of vasoactive substances, and by causing suppression of the vasodilatory systems. In addition, glucocorticoids may exert some hypertensive effects on cardiovascular regulation through the CNS via both glucocorticoid and mineralocorticoid receptors. Hypertension in CS usually resolves with surgical removal of the tumor, but some patients require pharmacological antihypertensive treatment both pre- and postoperatively. Thiazides and furosemide should be avoided, while adrenergic blockade and calcium channel antagonists are usually ineffective. Mineralocorticoid receptor antagonists, Ang II blockers and ACE inhibitors are good anti-hypertensive options; PPAR-γ agonists may help in many aspects of the insulin resistance syndrome. The relatively selective glucocorticoid receptor antagonist Mifepristone (RU 486) could reduce blood pressure in patients with CS. Neuromodulatory agents such as the serotonin inhibitors cyproheptadine and ritanserin, valproid acid, dopamine agonists, somatostatin analogs may occasionally be effective, as well as drugs acting directly at the adrenal levels, such as Ketoconazole and aminoglutetimide or even opDDD. Treating hypertension in CS remains a difficult task and a big challenge, in order to decrease the morbidity and mortality associated with the disease.

Incidentally discovered masses in hypertensive patients.

Endocrine hypertension is a term used for states in which hormone derangements result in clinically significant hypertension. The adrenal glands are the most likely culprits, due either to an excessive production of mineralocorticoids, catecholamines or glucocorticoids. The term 'adrenal incidentaloma' indicates an adrenal mass discovered accidentally during testing or treatment for other clinical conditions unrelated to any suspicion of adrenal disease. In particular, when an adrenal mass is discovered in a hypertensive subject, physicians must check whether the patient has pheochromocytoma, glucocorticoid excess or primary aldosteronism. Although most adrenal masses are non-hypersecretory adenomas, hormone screening can reveal a significant number of cases of clinically unsuspected hormone-secreting adrenal tumors. If the clinical history or physical examination of a patient with unilateral incidentaloma shows signs and symptoms suggestive of glucocorticoid, mineralocorticoid, adrenal sex hormone or catecholamine excess, which is confirmed biochemically, the treatment of choice is often adrenalectomy. In cases where surgery is contraindicated or the lesions are unresectable, medical treatment may be an option.