Laura Zinnamosca

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.

Adipokines and Cardiometabolic Profile in Primary Hyperaldosteronism

CONTEXT Primary aldosteronism (PA) has been recently associated with an unfavorable cardiometabolic profile. However, whether pro- and antiinflammatory adipokines levels can vary in PA is unknown. OBJECTIVE We evaluated the circulating levels of resistin, leptin, and adiponectin, echocardiographic left ventricle (LV) parameters, and the prevalence of metabolic syndrome (SM) in subjects with PA. PATIENTS Seventy-five subjects with established diagnosis of PA and 232 consecutive individuals with known or suspected hypertension were enrolled. MAIN OUTCOME MEASURES Plasma adipokine levels and echocardiographic parameters were calculated. Prevalence of SM was also estimated. RESULTS Among the 75 PA subjects, 37 patients were affected by aldosterone-producing adenoma and 38 by idiopathic hyperaldosteronism; 40 subjects were affected by essential hypertension (EH) and SM (EH SM+); 152 subjects were affected by EH without SM (EH SM-); and 40 subjects were normotensive (NT). Subjects with PA had the highest plasma resistin levels among the four groups (P < 0.01). Plasma resistin concentration was significantly higher in PA subjects when compared with EH SM+ individuals (P < 0.01) and EH SM- subjects (P < 0.01). PA subjects showed the higher LV mass and left atrium than EH individuals, irrespectively of the presence of SM (P < 0.01 for both). Plasma resistin levels was significantly correlated with ejection fraction and LV end-diastolic volume. The prevalence of SM was higher in PA subjects than in those with EH (25.4 vs. 20.3%). CONCLUSIONS Our data suggest that elevated aldosterone levels is associated with elevated circulating resistin levels and cardiac morphological changes independently of the presence of SM.

Bone and Mineral Metabolism in Patients with Primary Aldosteronism

Primary aldosteronism represents major cause of secondary hypertension, strongly associated with high cardiovascular morbidity and mortality. Aldosterone excess may influence mineral homeostasis, through higher urinary calcium excretion inducing secondary increase of parathyroid hormone. Recently, in a cohort of PA patients a significant increase of primary hyperparathyroidism was found, suggesting a bidirectional functional link between the adrenal and parathyroid glands. The aim of this study was to evaluate the impact of aldosterone excess on mineral metabolism and bone mass density. In 73 PA patients we evaluated anthropometric and biochemical parameters, renin-angiotensin-aldosterone system, calcium-phosphorus metabolism, and bone mineral density; control groups were 73 essential hypertension (EH) subjects and 40 healthy subjects. Compared to HS and EH, PA subjects had significantly lower serum calcium levels and higher urinary calcium excretion. Moreover, PA patients showed higher plasma PTH, lower serum 25(OH)-vitamin D levels, higher prevalence of vitamin D deficiency (65% versus 25% and 25%; P < 0.001), and higher prevalence of osteopenia/osteoporosis (38.5 and 10.5%) than EH (28% and 4%) and NS (25% and 5%), respectively. This study supports the hypothesis that bone loss and fracture risk in PA patients are potentially the result of aldosterone mediated hypercalciuria and the consecutive secondary hyperparathyroidism.

Oxidative stress in patients affected by primary aldosteronism

Objective: Primary aldosteronism, an important form of secondary hypertension, is associated with significant increase of cardiovascular risk (ischaemic heart, cerebrovascular events, arrhythmias) (relative risk 4.6). The specific treatment of primary aldosteronism significantly reduces cardiovascular risk. In addition to high blood pressure values and direct action of aldosterone, new mechanisms such as increased oxidative stress are involved in the development of organ damage, metabolic, endothelial and coagulation complications. Methods: The aim of the study was to evaluate parameters of oxidative stress in 38 patients (21 men, 17 women, mean age 53.3 ± 4.7 years) with primary aldosteronism [11 aldosterone-producing adenoma (APA) (4 men, 7 women, mean age 50.2 ± 4.5 years) and 27 idiopathic adrenal hyperplasia (IHA) (17 men, 10 women, mean age 54.5 ± 5.3 years)] at diagnosis and after specific treatment (surgical or pharmacological), with respect to 50 patients with essential hypertension (26 men, 24 women, mean age 49 ± 7.4 years) and 50 healthy individuals (28 men, 22 women, mean age 48.7 ± 4.4 years). Results: Patients with primary aldosteronism showed significant increase of NADPH oxidase (Nox2-dp) plasma levels and urinary isoprostanes (34.9 ± 4.3 &mgr;g/dl and 216.3 ± 15.7 ng/mg, respectively; P < 0.05) than essential hypertensive patients (27.1 ± 3.7 &mgr;g/dl and 144.8 ± 9.4 ng/mg, respectively; P < 0.05). In APA patients undergoing adrenalectomy, we observed significant reduction of both circulating levels of Nox2-dp (29 ± 2.1  vs. 22,4 ± 1.7 &mgr;g/dl; P < 0.05) and urinary levels of isoprostanes (221.1 ± 10.5 vs. 132.6 ± 8.7 ng/mg; P < 0.05). Conclusions: This is the first study showing an increased oxidative stress in primary aldosteronism, characterized by increased serum levels of Nox2-dp and urinary excretion of isoprostanes. After APA removal with laparoscopic adrenalectomy, we found reduction of serum Nox2-dp and urinary isoprostanes.

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/h2.7; 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.

Brown Fat Expresses Adiponectin in Humans

The presence of brown adipose tissue (BAT) in humans is unclear. Pheochromocytomas (PHEO) are rare tumors of neuroectodermal origin which occur in 0.1-0.2% of patients with hypertension. We sought to evaluate the presence and activity of BAT surrounding adrenal PHEO in a well-studied sample of 11 patients who were diagnosed with PHEO and then underwent adrenalectomy. Areas of white fat (WAT) and BAT surrounding PHEO were obtained by Laser Capture Microdissection for analysis of uncoupling protein (UCP)-1 and adiponectin mRNA expression. Adiponectin and UCP-1 mRNA levels were significantly higher in BAT than in WAT (0.62 versus 0.15 and 362.4 versus 22.1, resp., P < 0.01 for both). Adiponectin mRNA levels significantly correlated with urinary metanephrines (r = 0.76, P < 0.01), vanilly mandelic acid (VMA) (r = 0.95, P < 0.01), and serum adiponectin levels (r = 0.95, P < 0.01). Serum adiponectin levels significantly decreased (24.2 ± 2 μg/mL versus 18 ± 11 μg/mL, P < 0.01) after adrenalectomy in PHEO subjects. This study provides the following findings: (1) BAT surrounding PHEO expresses adiponectin and UCP-1 mRNA, (2) expression of adiponectin mRNA is significantly higher in BAT than in WAT surrounding PHEO, and (3) catecholamines and serum adiponectin levels significantly correlate with BAT UCP-1 and adiponectin mRNA.

Clinical experience with pheochromocytoma in a single centre over 16 years.

AbstractBackground: Pheochromocytoma and paraganglioma are rare tumours of neuroectodermal origin. Pheochromocytoma occurs in 0.1–2% of people with hypertension, while the incidence rises to 4–5% in patients with incidental adrenal mass. Aim: To analyse the presentation, diagnosis and localization, pathology, molecular genetic aspects, surgical management and long-term outcome of a large series of patients with pheochromocytoma referred to a single centre. Methods: From 1992 to 2008, we observed 91 patients with pheochromocytoma, 70 (77%) with the sporadic form and 21 (23%) with the hereditary form. In the group with the hereditary form, the mean age at diagnosis was significantly lower than the mean age of the group with the sporadic form (38 vs 48 years; p < 0.001). Results: Eighty (88%) patients with pheochromocytoma were symptomatic and the classical triad of palpitations, headache and diaphoresis was present in 30% of patients. In 12% of patients, the pheochromocytoma was discovered during radiological images (adrenal incidentaloma). The unilateral adrenal localization was observed in 78% of patients, bilateral in 15% and extra-adrenal in 7% of patients. All pheochromocytoma patients underwent surgical procedure and the laparotomic approach was used in 49 (53%) patients, while the laparoscopic approach was performed in 42 (47%) patients. Pheochromocytoma was benign in 86 patients (93%) [mean size was 4.3 cm] and the malignant form was found in five patients (7%) [mean size was 10 cm]. Conclusions: These data from a large cohort of patients are consistent with those reported in the literature and show that pheochromocytoma is an in important challenge for clinicians.

Leptin and Adiponectin mRNA Expression From the Adipose Tissue Surrounding the Adrenal Neoplasia

CONTEXT Interplay between adipose tissue and adrenal glands has been recently suggested, without well-founded actions of locally adipose tissue surrounding the adrenal glands. OBJECTIVE We hypothesized that the local expression of leptin and adiponectin can be associated with pathological changes of the adrenal glands. PATIENTS AND MAIN OUTCOME MEASURES We evaluated RT-PCR of leptin and adiponectin mRNA expression from the adipose tissue surrounding adrenal glands in 30 patients, collecting adipose tissue surrounding the adrenal neoplasms, peri-renal and subcutaneous depots. RESULTS Leptin mRNA levels from adrenal neoplasia and peri-renal fat were significantly higher in aldosterone-producing adenoma than in nonfunctioning adenomas (P < 0.001 and P < 0.02, respectively). In patients with Cushings syndrome leptin mRNA levels were significantly higher in adrenal fat than in peri-renal (P < 0.05) and subcutaneous adipose tissue (P < 0.001). Adiponectin mRNA expression from adrenal neoplasia was significantly lower than that from peri-renal and subcutaneous fat depots (P < 0.05). Leptin and adiponectin plasma levels significantly correlated with their mRNA expression from the fat depot surrounding the adrenal neoplasia. CONCLUSIONS Our findings suggest an active role of the fat depot surrounding the adrenal neoplasia, with local secretion of leptin and adiponectin.

Epicardial Fat Thickness and Primary Aldosteronism.

Primary aldosteronism (PA) is associated with increased cardiovascular risk and left ventricle (LV) changes. Given its peculiar biomolecular and anatomic properties, excessive epicardial fat, the heart-specific visceral fat depot, can affect LV morphology. Whether epicardial fat can be associated with aldosterone and LV mass (LVM) in patients with PA is unknown. We performed ultrasound measurement of the epicardial fat thickness (EAT) in 79 consecutive newly diagnosed patients with PA, 59 affected by bilateral adrenal hyperplasia (IHA), 20 aldosterone-producing adenoma (APA), and 30 patients with essential hypertension (low renin hypertension) (EH). The 3 groups did not differ by age, sex distribution, body mass index (BMI), waist circumference (WC), or blood pressure values. EAT showed a trend of increase in both APA and IHA groups when compared to patients with EH (8.3±1.8 vs. 7.9±1.3 vs. 7.8±2 mm, respectively). EAT was significantly correlated with indexed LVM in the IHA group (r=0.35, p<005), better than BMI or WC were. Interestingly, EAT was highly associated with plasma aldosterone concentrations (PAC) and PAC/plasma renin activity (PRA) (PAC/PRA) in the APA group (p=0.58, p=0.37, p<0.01, for both), whereas BMI and WC were not. EAT was also correlated with PRA in the IHA group (p=-0.28, p<0.05). Our study indicates a novel and interesting interaction of EAT with PA, independent of obesity, abdominal fat and blood pressure control. EAT can locally affect LVM, at least in patients with IHA. Further studies in larger population will be required to confirm these findings.

Enhanced Soluble Serum CD40L and Serum P-Selectin Levels in Primary Aldosteronism

Primary aldosteronism (PA) is one of the most frequent forms of secondary hypertension, associated with atherosclerosis and higher risk of cardiovascular events. Platelets play a key role in the atherosclerotic process. The aim of the study was to evaluate the platelet activation by measuring serum levels of soluble CD40L (sCD40L) and P-selectin (sP-selectin) in consecutive PA patients [subgroup: aldosterone-secreting adrenal adenoma (APA) and bilateral adrenal hyperplasia (IHA)], matched with essential hypertensive (EH) patients. The subgroup of APA patients was revaluated 6-months after unilateral adrenalectomy. In all PA group, we measured higher serum levels of both sP-selectin (14.29±9.33 pg/ml) and sCD40L (9.53±4.2 ng/ml) compared to EH patients (9.39±5.3 pg/ml and 3.54±0.94 ng/ml, respectively; p<0.001). After removal of APA, PA patients showed significant reduction of blood pressure (BP) values, plasma aldosterone (PAC) levels and ARR-ratio, associated with a significant reduction of sP-selectin (16.74±8.9 pg/ml vs. 8.1±3.8 pg/ml; p<0.01) and sCD40L (8.6±1 ng/ml vs. 5.24±0.94 ng/ml; p<0.001). In PA patients, we found a significant correlation between sP-selectin and sCD40L with PAC (r=0.52, p<0.01; r=0.50, p<0.01, respectively); this correlation was stronger in APA patients (r=0.54; p<0.01 r=0.63; p<0.01, respectively). Our results showed that PA is related to platelet activation, expressed as higher plasma values of sCD40L and sP-selectin values. Surgical treatment and consequent normalization of aldosterone secretion was associated with significant reduction of sCD40L and sP-selectin values in APA patients.