The Effects of Polyphenols on Bone Metabolism in Postmenopausal Women: Systematic Review and Meta-Analysis of Randomized Control Trials

Osteoporosis is a condition favored by the postmenopausal decline in estrogen levels and worsened by oxidative stress (OS). Polyphenols are natural compounds abundantly found in fruits and vegetables, and they exert antioxidant and hormonal effects that could be useful in osteoporosis prevention, as suggested by epidemiological studies showing a lower incidence of fractures in individuals consuming polyphenol-rich diets. The aim of our meta-analysis is to evaluate the effects of polyphenols on bone mineral density (BMD, primary endpoint) and bone turnover markers (BTMs, secondary endpoint) in postmenopausal women. Twenty-one randomized control trials (RCTs) were included in our analysis after in-depth search on PubMed, EMBASE, and Scopus databases. We found that supplementation with polyphenols for 3-36 months exerted no statically significant effects on BMD measured at lumbar spine (sMD: 0.21, 95% CI [-0.08 to 0.51], p = 0.16), femoral neck (sMD: 0.16, 95% CI [-0.23 to 0.55], p = 0.42), total hip (sMD: 0.05, 95% CI [-0.14 to 0.24], p = 0.61), and whole body (sMD: -0.12, 95% CI [-0.42 to 0.17], p = 0.41). Subgroup analysis based on treatment duration showed no statistical significance, but a significant effect on lumbar BMD emerged when studies with duration of 24 months or greater were analyzed separately. On the other hand, we found a significantly slight increase in bone-specific alkaline phosphatase (BALP) levels (sMD: 1.27, 95% CI [1.13 to 1.42], p < 0.0001) and a decrease in pyridinoline (PD) levels (sMD: -0.58, 95% CI [-0.77 to -0.39], p < 0.0001). High heterogeneity among studies and unclear risk of bias in one third of the included studies emerged. A subgroup analysis showed similar effects for different duration of treatment and models of dual-energy X-ray absorptiometry (DXA) scanner. More robust evidence is needed before recommending the prescription of polyphenols in clinical practice.

Pro-Osteogenic and Anti-Inflammatory Synergistic Effect of Orthosilicic Acid, Vitamin K2, Curcumin, Polydatin and Quercetin Combination in Young and Senescent Bone Marrow-Derived Mesenchymal Stromal Cells

During aging, bone marrow mesenchymal stromal cells (MSCs)-the precursors of osteoblasts-undergo cellular senescence, losing their osteogenic potential and acquiring a pro-inflammatory secretory phenotype. These dysfunctions cause bone loss and lead to osteoporosis. Prevention and intervention at an early stage of bone loss are important, and naturally active compounds could represent a valid help in addition to diet. Here, we tested the hypothesis that the combination of two pro-osteogenic factors, namely orthosilicic acid (OA) and vitamin K2 (VK2), and three other anti-inflammatory compounds, namely curcumin (CUR), polydatin (PD) and quercetin (QCT)-that mirror the nutraceutical BlastiMin Complex^® (Mivell, Italy)-would be effective in promoting MSC osteogenesis, even of replicative senescent cells (sMSCs), and inhibiting their pro-inflammatory phenotype in vitro. Results showed that when used at non-cytotoxic doses, (i) the association of OA and VK2 promoted MSC differentiation into osteoblasts, even when cultured without other pro-differentiating factors; and (ii) CUR, PD and QCT exerted an anti-inflammatory effect on sMSCs, and also synergized with OA and VK2 in promoting the expression of the pivotal osteogenic marker ALP in these cells. Overall, these data suggest a potential role of using a combination of all of these natural compounds as a supplement to prevent or control the progression of age-related osteoporosis.

Remote management of osteoporosis in the first wave of the COVID-19 pandemic

We conducted a survey during the first pandemic wave of coronavirus disease 2019 (COVID-19) on a large group of osteoporotic patients to evaluate the general conditions of osteoporotic patients and the impact of the pandemic on the management of osteoporosis, finding high compliance to treatments and low COVID-19 lethality.

INTRODUCTION

During the first pandemic wave of coronavirus disease 2019 (COVID-19), 209,254 cases were diagnosed in Italy; fatalities were 26,892 and were overwhelmingly older patients. The high prevalence of osteoporosis in this age group suggests a potential relationship between SARS-CoV-2 infection and bone metabolism.

METHODS

In a telephone survey conducted from April to May 2020, patients from the Osteoporosis Center, Clinic of Endocrinology and Metabolic Diseases of Umberto I Hospital (Ancona, Italy), were interviewed to evaluate the general clinical conditions of osteoporotic patients, compliance with osteoporosis medications, COVID-19 prevalence, hospitalization rate, COVID-19 mortality, and lethality.

RESULTS

Among the 892 patients interviewed, 77.9% were taking osteoporosis treatment and 94.6% vitamin D supplementation as prescribed at the last visit. COVID-19-like symptoms were reported by 5.1%, whereas confirmed cases were 1.2%. A total number of 33 patients had been in hospital and the hospitalization rate of those who had not discontinued vitamin D supplementation was less than 4%. There were eight deaths, two with a concomitant COVID-19 diagnosis. The prevalence of severe osteoporosis was 50% in total COVID-19 patients and 87.5% in deceased COVID-19 patients. The overall COVID-19 mortality was 0.2%; lethality was 20%, lower than the national rate of the same age group.

CONCLUSIONS

This large group of osteoporotic patients showed high compliance and lower COVID-19 lethality compared to patients of the same age. Novel approaches such as telemedicine can provide critical support for the remote follow-up of patients with chronic diseases also in the setting of routine care.

Bone Metabolism in SARS-CoV-2 Disease: Possible Osteoimmunology and Gender Implications

Even though inflammatory conditions are known to exert adverse effects on bone metabolism, there are no published data regarding SARS-CoV-2 infection and subsequent fracture risk. We present a brief review of the molecular mechanisms linking inflammatory diseases to increased fracture risk/osteoporosis and of the therapeutic strategies that can prevent bone resorption in patients with inflammatory disease, focusing on the RANK-RANKL system. We also make some considerations on gender differences in infection response and on their implications for survival and for the consequences of COVID-19. Several inflammatory cytokines, especially IL-1, IL-6, and TNF-α, stimulate osteoclast activity, favoring bone resorption through the RANK-RANKL system. Data from the previous SARS-CoV outbreak suggest that the present disease also has the potential to act directly on bone resorption units, although confirmation is clearly needed. Even though the available data are limited, the RANK-RANKL system may provide the best therapeutic target to prevent bone resorption after COVID-19 disease. Vitamin D supplementation in case of deficiency could definitely be beneficial for bone metabolism, as well as for the immune system. Supplementation of vitamin D in case of deficiency could be further advantageous. In COVID-19 patients, it would be useful to measure the bone metabolism markers and vitamin D. Targeting the RANK-RANKL system should be a priority, and denosumab could represent a safe and effective choice. In the near future, every effort should be made to investigate the fracture risk after SARS-CoV-2 infection.

The 2020 Italian Society of Arterial Hypertension (SIIA) practical guidelines for the management of primary aldosteronism

Background and aim

Considering the amount of novel knowledge generated in the last five years, a team of experienced hypertensionlogists was assembled to furnish updated clinical practice guidelines for the management of primary aldosteronism.

Methods

To identify the most relevant studies, the authors utilized a systematic literature review in international databases by applying the PICO strategy, and then they were required to make use of only those meeting predefined quality criteria. For studies of diagnostic tests, only those that fulfilled the Standards for Reporting of Diagnostic Accuracy recommendations were considered.

Results

Each section was jointly prepared by at least two co-authors, who provided Class of Recommendation and Level of Evidence following the American Heart Association methodology. The guidelines were sponsored by the Italian Society of Arterial Hypertension and underwent two rounds of revision, eventually reexamined by an External Committee. They were presented and thoroughly discussed in two face-to-face meetings with all co-authors and then presented on occasion of the 36th Italian Society of Arterial Hypertension meeting in order to gather further feedbacks by all members. The text amended according to these feedbacks was subjected to a further peer review.

Conclusions

After this process, substantial updated information was generated, which could simplify the diagnosis of primary aldosteronism and assist practicing physicians in optimizing treatment and follow-up of patients with one of the most common curable causes of arterial hypertension.

Primary Aldosteronism and Obstructive Sleep Apnea: A Cross-Sectional Multi-Ethnic Study

The association between primary aldosteronism (PA) and obstructive sleep apnea (OSA) has been a matter of debate. 2016 Endocrine Society guideline recommends screening for PA all hypertensive patients with OSA. We designed a multicenter, multiethnic, cross-sectional study to evaluate the prevalence of PA in patients with OSA and the prevalence of OSA in unselected patients with PA. Two hundred and three patients with OSA (102 whites and 101 Chinese) were screened for PA, and 207 patients with PA (104 whites, 100 Chinese, and 3 of African descent) were screened for OSA by cardiorespiratory polygraphy. Eighteen patients with OSA (8.9%) had PA (11.8% of white and 5.9% of Chinese ethnicity). In patients without other indications for PA screening, the prevalence of PA dropped to 1.5%. The prevalence of OSA in patients with PA was 67.6%, consistent in both white and Chinese patients. A correlation between aldosterone levels and apnea/hypopnea index was observed in white patients with PA (R²=0.225, P=0.016) but not in Chinese patients. Multinomial logistic regression confirmed a significant and independent association between plasma aldosterone levels and moderate to severe OSA diagnosis in white patients (odds ratio, 1.002; P=0.002). In conclusion, aldosterone levels may contribute to the severity of OSA in white patients with hyperaldosteronism, but patients with OSA are not at high risk of PA. Results of the present study challenge the current recommendation of the Endocrine Society guideline that all patients with OSA should be screened for PA, irrespective of the grade of hypertension.

Computed Tomography and Adrenal Venous Sampling in the Diagnosis of Unilateral Primary Aldosteronism

Unilateral primary aldosteronism is the most common surgically correctable form of endocrine hypertension and is usually differentiated from bilateral forms by adrenal venous sampling (AVS) or computed tomography (CT). Our objective was to compare clinical and biochemical postsurgical outcomes of patients with unilateral primary aldosteronism diagnosed by CT or AVS and identify predictors of surgical outcomes. Patient data were obtained from 18 internationally distributed centers and retrospectively analyzed for clinical and biochemical outcomes of adrenalectomy of patients with surgical management based on CT (n=235 patients, diagnosed from 1994-2016) or AVS (526 patients, diagnosed from 1994-2015) using the standardized PASO (Primary Aldosteronism Surgical Outcome) criteria. Biochemical outcomes were highly different according to surgical management approach with a smaller proportion in the CT group achieving complete biochemical success (188 of 235 [80%] patients versus 491 of 526 [93%], P<0.001) and a greater proportion with absent biochemical success (29 of 235 [12%] versus 10 of 526 [2%], P<0.001). A diagnosis by CT was associated with a decreased likelihood of complete biochemical success compared with AVS (odds ratio, 0.28; 0.16-0.50; P<0.001). Clinical outcomes were not significantly different, but the absence of a postsurgical elevated aldosterone-to-renin ratio was a strong marker of complete clinical success (odds ratio, 14.81; 1.76-124.53; P=0.013) in the CT but not in the AVS group. In conclusion, patients diagnosed by CT have a decreased likelihood of achieving complete biochemical success compared with a diagnosis by AVS.

Adrenalectomy Lowers Incident Atrial Fibrillation in Primary Aldosteronism Patients at Long Term

Primary aldosteronism (PA) causes cardiovascular damage in excess to the blood pressure elevation, but there are no prospective studies proving a worse long-term prognosis in adrenalectomized and medically treated patients. We have, therefore, assessed the outcome of PA patients according to treatment mode in the PAPY study (Primary Aldosteronism Prevalence in Hypertension) patients, 88.8% of whom were optimally treated patients with primary (essential) hypertension (PH), and the rest had PA and were assigned to medical therapy (6.4%) or adrenalectomy (4.8%). Total mortality was the primary end point; secondary end points were cardiovascular death, major adverse cardiovascular events, including atrial fibrillation, and total cardiovascular events. Kaplan-Meier and Cox analysis were used to compare survival between PA and its subtypes and PH patients. After a median of 11.8 years, complete follow-up data were obtained in 89% of the 1125 patients in the original cohort. Only a trend (P=0.07) toward a worse death-free survival in PA than in PH patients was observed. However, at both univariate (90.0% versus 97.8%; P=0.002) and multivariate analyses (hazard ratio, 1.82; 95% confidence interval, 1.08-3.08; P=0.025), medically treated PA patients showed a lower atrial fibrillation-free survival than PH patients. By showing that during a long-term follow-up adrenalectomized aldosterone-producing adenoma patients have a similar long-term outcome of optimally treated PH patients, whereas, at variance, medically treated PA patients remain at a higher risk of atrial fibrillation, this large prospective study emphasizes the importance of an early identification of PA patients who need adrenalectomy as a key measure to prevent incident atrial fibrillation.

ATP2C1 gene mutations in Hailey-Hailey disease and possible roles of SPCA1 isoforms in membrane trafficking

ATP2C1 gene codes for the secretory pathway Ca(2+)/Mn(2+)-ATPase pump type 1 (SPCA1) localizing at the golgi apparatus. Mutations on the human ATP2C1 gene, causing decreased levels of the SPCA1 expression, have been identified as the cause of the Hailey-Hailey disease, a rare skin disorder. In the last few years, several mutations have been described, and here we summarize how they are distributed along the gene and how missense mutations affect protein expression. SPCA1 is expressed in four different isoforms through alternative splicing of the ATP2C1 gene and none of these isoforms is differentially affected by any of these mutations. However, a better understanding of the tissue specific expression of the isoforms, their localization along the secretory pathway, their specific binding partners and the role of the C-terminal tail making isoforms different from each other, will be future goals of the research in this field.

Hypovitaminosis D and organ damage in patients with arterial hypertension: a multicenter double blind randomised controlled trial of cholecalciferol supplementation (HYPODD) : study design, clinical procedures and treatment protocol

INTRODUCTION

At this time, good quality randomized clinical trials assessing the effects of vitamin D supplementation on cardiometabolic outcomes are lacking in the international literature.

AIM

To fill this gap, the Working Group on Vitamin D and Cardiorenal Disorders established jointly by the Italian Society of Hypertension (SIIA) and the Forum in Bone and Mineral Research conceived the HYPODD study (HYPOvitaminosis D and organ Damage).

METHODS

HYPODD is a no-profit multicenter 12-month parallel-group double-blind placebo controlled randomized trial aiming to assess the effects of cholecalciferol supplementation on blood pressure control, antihypertensive drugs consumption and progression of target organ damage in patients with essential hypertension and 25-hydroxyvitamin D serum level lower than 20 ng/ml (vitamin D deficiency). HYPODD is coordinated by the European Society Excellence Center of Hypertension of Federico II University, Naples, and involves 12 academic institutions in Italy (Ancona, Milan, Padua, Perugia, Rome, Siena, Trieste, Turin, Udine, Varese, and Verona).

RESULTS AND CONCLUSION

The HYPODD study has been registered at the Agenzia Italiana del Farmaco-Osservatorio sulla Sperimentazione Clinica del Farmaco (AIFA-OsSC) and EUDRACT sites (n° 2012-003514-14) and has been approved by the Ethical Committees of all the Centers involved in the study. The patients' recruitment is currently underway.

Rare diseases in clinical endocrinology: a taxonomic classification system

PURPOSE

Rare endocrine-metabolic diseases (REMD) represent an important area in the field of medicine and pharmacology. The rare diseases of interest to endocrinologists involve all fields of endocrinology, including rare diseases of the pituitary, thyroid and adrenal glands, paraganglia, ovary and testis, disorders of bone and mineral metabolism, energy and lipid metabolism, water metabolism, and syndromes with possible involvement of multiple endocrine glands, and neuroendocrine tumors. Taking advantage of the constitution of a study group on REMD within the Italian Society of Endocrinology, consisting of basic and clinical scientists, a document on the taxonomy of REMD has been produced.

METHODS AND RESULTS

This document has been designed to include mainly REMD manifesting or persisting into adulthood. The taxonomy of REMD of the adult comprises a total of 166 main disorders, 338 including all variants and subtypes, described into 11 tables.

CONCLUSIONS

This report provides a complete taxonomy to classify REMD of the adult. In the future, the creation of registries of rare endocrine diseases to collect data on cohorts of patients and the development of common and standardized diagnostic and therapeutic pathways for each rare endocrine disease is advisable. This will help planning and performing intervention studies in larger groups of patients to prove the efficacy, effectiveness, and safety of a specific treatment.

Vitamin D levels and bone mineral density: are LH levels involved in the pathogenesis of bone impairment in hypogonadal men?

BACKGROUND

Osteoporosis is a major public health problem also in men and it recognizes hypogonadism as a major cause.

AIMS

To investigate the possible pathogenetic mechanisms on bone impairment in male hypogonadism and on its improvement in response to testosterone replacement treatment (TRT).

METHODS

We retrospectively investigated the hormonal profile and bone mineral density (BMD), evaluated by DXA, in 17 middle-aged hypogonadal men treated for at least 5 years with TRT, compared with 21 recently diagnosed untreated hypogonadal males and 18 age- and BMI-matched healthy subjects.

RESULTS

No significant differences in clinical, biochemical and densitometric parameters were found among the three groups, with the exception of 25-OH vitamin D levels that were significantly higher in healthy subjects compared with hypogonadal patients. Untreated patients affected by central hypogonadism, despite similar hormonal levels, displayed significantly lower BMD and decreased LH and 25-OH vitamin D levels, compared with patients with primary hypogonadism. Among the treated patients, BMD parameters were similar regardless of the formulation of TRT.

CONCLUSIONS

A recent history of central hypogonadism, compared with primary hypogonadism, appears to adversely affect bone health independently of gonadal steroids levels. This could be due to lower LH levels and consequent reduction of vitamin D 25-hydroxylation in the testis.

Aldosterone suppression on contralateral adrenal during adrenal vein sampling does not predict blood pressure response after adrenalectomy

CONTEXT

Adrenal vein sampling (AVS) is the only reliable means to distinguish between aldosterone-producing adenoma and bilateral adrenal hyperplasia, the two most common subtypes of primary aldosteronism (PA). AVS protocols are not standardized and vary widely between centers.

OBJECTIVE

The objective of the study was to retrospectively investigate whether the presence of contralateral adrenal (CL) suppression of aldosterone secretion was associated with improved postoperative outcomes in patients who underwent unilateral adrenalectomy for PA.

SETTING

The study was carried out in eight different referral centers in Italy, Germany, and Japan.

PATIENTS

From 585 consecutive AVS in patients with confirmed PA, 234 procedures met the inclusion criteria and were used for the subsequent analyses.

RESULTS

Overall, 82% of patients displayed contralateral suppression. This percentage was significantly higher in ACTH stimulated compared with basal procedures (90% vs 77%). The CL ratio was inversely correlated with the aldosterone level at diagnosis and, among AVS parameters, with the lateralization index (P = .02 and P = .01, respectively). The absence of contralateral suppression was not associated with a lower rate of response to adrenalectomy in terms of both clinical and biochemical parameters, and patients with CL suppression underwent a significantly larger reduction in the aldosterone levels after adrenalectomy.

CONCLUSIONS

For patients with lateralizing indices of greater than 4 (which comprised the great majority of subjects in this study), CL suppression should not be required to refer patients to adrenalectomy because it is not associated with a larger blood pressure reduction after surgery and might exclude patients from curative surgery.

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.

Primary aldosteronism and essential hypertension: assessment of cardiovascular risk at diagnosis and after treatment

BACKGROUND AND AIMS

Primary aldosteronism (PA), the most frequent form of secondary hypertension, is characterized by a higher rate of cardiovascular (CV) events than essential hypertension (EH). Aim of the study was to evaluate the cardiovascular risk according to the ESH/ESC 2007 guidelines, in patients with PA and with EH, at diagnosis and after treatment.

METHODS AND RESULTS

We prospectively studied 102 PA patients (40 with aldosterone producing adenoma-APA and 62 with idiopathic hyperaldosteronism-IHA) and 132 essential hypertensives at basal and after surgical or medical treatment (mean follow-up period 44 months for PA and 42 months for EH). At baseline evaluation the stratification of CV risk was significantly different: the predominant risk category was the high CV risk (50% in total PA, 53% in PA matched for blood pressure values and 55% in EH), but the very high risk category was twice in PA than in EH patients (36% in total PA and 33% in matched PA vs. 17% in EH, p < 0.05). The worse risk profile of PA was due to a higher prevalence of glycemic alterations, metabolic syndrome and left ventricular hypertrophy (LVH) (p < 0.05). After adequate treatment, the CV risk was significantly reduced becoming comparable in PA and in EH patient due to a reduction of hypertension grading, prevalence of metabolic syndrome, hypertension persistence and LVH (p < 0.05).

CONCLUSION

Patients with PA present a high CV risk, which is in part reversible after specific treatment, due both to the reduced blood pressure values and to the improvement of end-organ damage.

Somatic ATP1A1 , ATP2B3 , and KCNJ5 Mutations in Aldosterone-Producing Adenomas

Aldosterone-producing adenomas (APAs) cause a sporadic form of primary aldosteronism and somatic mutations in the KCNJ5 gene, which encodes the G-protein–activated inward rectifier K + channel 4, GIRK4, account for ≈40% of APAs. Additional somatic APA mutations were identified recently in 2 other genes, ATP1A1 and ATP2B3 , encoding Na + /K + -ATPase 1 and Ca 2+ -ATPase 3, respectively, at a combined prevalence of 6.8%. We have screened 112 APAs for mutations in known hotspots for genetic alterations associated with primary aldosteronism. Somatic mutations in ATP1A1 , ATP2B3 , and KCNJ5 were present in 6.3%, 0.9%, and 39.3% of APAs, respectively, and included 2 novel mutations (Na + /K + -ATPase p.Gly99Arg and GIRK4 p.Trp126Arg). CYP11B2 gene expression was higher in APAs harboring ATP1A1 and ATP2B3 mutations compared with those without these or KCNJ5 mutations. Overexpression of Na + /K + -ATPase p.Gly99Arg and GIRK4 p.Trp126Arg in HAC15 adrenal cells resulted in upregulation of CYP11B2 gene expression and its transcriptional regulator NR4A2. Structural modeling of the Na + /K + -ATPase showed that the Gly99Arg substitution most likely interferes with the gateway to the ion binding pocket. In vitro functional assays demonstrated that Gly99Arg displays severely impaired ATPase activity, a reduced apparent affinity for Na + activation of phosphorylation and K + inhibition of phosphorylation that indicate decreased Na + and K + binding, respectively. Moreover, whole cell patch-clamp studies established that overexpression of Na + /K + -ATPase Gly99Arg causes membrane voltage depolarization. In conclusion, somatic mutations are common in APAs that result in an increase in CYP11B2 gene expression and may account for the dysregulated aldosterone production in a subset of patients with sporadic primary aldosteronism.

Bone health and aldosterone excess

A picture of hyperparathyroidism secondary to increased urinary calcium excretion was found in 116 patients with primary aldosteronism (PA), compared with 110 essential hypertensives. After medical or surgical treatment in 40 PA patients, parathyroid hormone (PTH) levels were significantly reduced and bone mineral density (BMD) significantly increased at the lumbar spine, femoral neck, and total hip.

INTRODUCTION

Recent studies have shown that aldosterone induces urinary calcium excretion leading to a reduction of calcemia with consequent secondary hyperparathyroidism and BMD loss. In patients with PA, this picture of hyperparathyroidism is significantly improved by treatment with adrenal surgery or with mineralocorticoid receptor antagonists. On these premises, the aim of the present study was to evaluate calcium and phosphate metabolism parameters in PA patients, compared with patients with essential hypertension (EH) and the effect of treatment of aldosterone excess on bone health in PA patients.

METHODS

We studied 226 patients: 116 with PA (46 with an aldosterone-producing adenoma and 70 with bilateral adrenal hyperplasia) and 110 patients with EH. In 40 patients with PA, we evaluated biochemical parameters and bone mass, using the dual-energy X-ray absorptiometry, at baseline and after a mean follow-up of 24 months from treatment.

RESULTS

In PA patients, compared with EH, PTH levels and urinary calcium excretion significantly increased while serum calcium significantly decreased with comparable vitamin D levels. At follow-up in PA patients, PTH levels were significantly reduced compared with basal evaluation, despite similar vitamin D amounts. At follow-up, we observed a significant improvement of the Z-score at the lumbar spine, femoral neck, and at total hip sites.

CONCLUSIONS

Our results support previous data showing secondary hyperparathyroidism in PA patients, which is reversible after treatment. Moreover, this targeted treatment appears to be able to determine a significant improvement of BMD both at the spine and hip sites.

Cortical adrenal mitochondrial morphology changes in functional state: new insights

We compared changes in the morphology of mitochondrial cristae with those in the blood and adrenal content of steroid hormones after the stimulation or inhibition of steroidogenesis. Rats were treated with adrenocorticotrophic hormone or angiotensin II to elicit steroidogenesis and with dexamethasone to inhibit it. Blood and adrenal glands were collected after several time intervals for measurements of steroids and their main intermediates. In the zona fasciculata, mitochondrial ultrastructure was investigated by high resolution scanning electron microscopy. We found that the morphometric data correlated well with the measurements of hyper- or hypo-activity of steroidogenesis over short periods of time (4 h) but not over longer observation times. A peculiar finding was that, contrary to previous reports, 11-deoxycortisol was present in adult rat adrenal tissue.

Visceral adipose tissue: emerging role of gluco- and mineralocorticoid hormones in the setting of cardiometabolic alterations

Several clinical and experimental lines of evidence have highlighted the detrimental effects of visceral adipose tissue excess on cardiometabolic parameters. Besides, recent findings have shown the effects of gluco-and mineralocorticoid hormones on adipose tissue and have also underscored the interplay existing between such adrenal steroids and their respective receptors in the modulation of adipose tissue biology. While the fundamental role played by glucocorticoids on adipocyte differentiation and storage was already well known, the relevance of the mineralocorticoids in the physiology of the adipose organ is of recent acquisition. The local and systemic renin–angiotensin–aldosterone system (RAAS) acting on adipose tissue seems to contribute to the development of the cardiometabolic phenotype so that its modulation can have deep impact on human health. A better understanding of the pathophysiology of the adipose organ is of crucial importance in order to identify possible therapeutic approaches that can avoid the development of such cardiovascular and metabolic sequelae.

Blood pressure, thyroid-stimulating hormone, and thyroid disease prevalence in primary aldosteronism and essential hypertension

BACKGROUND

A positive correlation between thyroid-stimulating hormone (TSH) and blood pressure (BP) has been identified in normotensives and in patients with essential hypertension (EH). This study was designed to evaluate, in primary aldosteronism (PA) and in EH, potential association of BP, TSH, and ultrasonographic changes of the thyroid.

METHODS

We studied 188 patients: 92 with PA and 96 matched essential hypertensives. Clinical and ambulatory BP (ABP), and thyroid function were evaluated in all patients. In PA and in a subgroup of EH patients (n = 65) thyroid ultrasonography was performed.

RESULTS

In PA patients, diastolic office and diastolic ABP increased across TSH quartiles and multivariate analysis confirmed a positive significant correlation between TSH and diastolic BP, independently of aldosterone levels, body mass index (BMI), duration of hypertension, and age. In EH patients, we found a significant linear increase in systolic and diastolic ABP with increasing TSH. The prevalence of thyroid dysfunctions was similar in PA and EH (15% and 19%, respectively). In PA patients, we found a higher prevalence of ultrasonographic alterations than in EH (66% vs. 46%, P < 0.05). PA patients presenting morphological abnormalities had higher homeostasis model assessment-insulin resistance levels than patients with normal gland at ultrasonography (4.2 ± 1.8 vs. 3.1 ± 0.8 P < 0.05).

CONCLUSIONS

We found a positive correlation between TSH and BP both in PA and EH patients. Moreover, in PA patients we observed a high prevalence of thyroid morphological alterations.

The Functional c.-2G>C Variant of the Mineralocorticoid Receptor Modulates Blood Pressure, Renin, and Aldosterone Levels

The mineralocorticoid receptor (MR) is essential in the regulation of volemia and blood pressure. Rare mutations in the MR gene cause type 1 pseudohypoaldosteronism and hypertension. In this study we characterized the common MR polymorphism c.-2G>C (rs2070951) in vitro and tested its influence on parameters related to blood pressure regulation and the renin-angiotensin system. In vitro studies showed that the G allele was associated with decreased MR protein levels and reduced transcriptional activation compared with the C allele. Association studies were performed with several outcome variables in 3 independent cohorts: a mild hypertensive group subjected to a salt-sensitivity test, a healthy normotensive group included in a crossover study to receive both a high and low Na/K diet, and a large cohort (The Netherlands Study of Depression and Anxiety), in which blood pressure was measured. Subjects with the GG genotype had significantly higher plasma renin levels both in the mild hypertensive group and in normal volunteers compared with homozygous C carriers. The GG genotype was also correlated with higher plasma aldosterone levels in healthy subjects. In both the mild hypertensive group and The Netherlands Study of Depression and Anxiety cohort the genotype GG was associated with higher systolic blood pressure in males. In conclusion, the G allele of the common functional genetic polymorphism c.-2G>C in the MR gene associates with increased activation of the renin-angiotensin-aldosterone axis and with increased blood pressure, probably related to decreased MR expression.

Analysis of insulin sensitivity in adipose tissue of patients with primary aldosteronism

OBJECTIVE

The objective of the study was to assess the effect of high aldosterone levels on insulin sensitivity of adipose tissue in humans.

METHODS

Visceral adipose tissue (VAT) was obtained from patients with aldosterone-producing adenoma (APA; n=14) and, as controls, nonfunctioning adenoma (NFA; n=14) undergoing laparoscopic adrenalectomy. Homeostasis model assessment index was higher and potassium was lower in APA than NFA (P<0.05). Immunohistochemistry, Western blotting, and real-time PCR were used to detect and quantify mineralocorticoid receptor (MR) expression. Transcript levels of peroxisome proliferative-activated receptor-gamma, insulin receptor, glucose transporter 4, insulin receptor substrate-1 and -2, leptin, adiponectin, IL-6, monocyte chemoattractant protein-1, glucocorticoid receptor (GR)-alpha, 11beta-hydroxysteroid dehydrogenase (HSD11B) type 1, and HSD11B2 were quantified. The effect of increasing aldosterone concentrations on 2-deoxy-[3H]d-glucose uptake was tested in human sc abdominal adipocytes.

RESULTS

Expression of MR was demonstrated in VAT, with no difference between APA and NFA as to mRNA levels of MR, GRalpha, HSD11B1, and glucose metabolism and inflammation factors. In cultured adipocytes, basal and insulin-stimulated glucose uptake were unaffected by 1-100 nM (normal/hyperaldosteronism) and impaired only by much higher, up to 10 microM, aldosterone concentrations. The impairment was prevented by RU486 but not by eplerenone.

CONCLUSIONS

Gene expression of insulin signaling/inflammatory molecules was similar in VAT of APA and NFA patients, not supporting an effect of aldosterone excess on insulin sensitivity of adipose tissues. Only at pharmacological concentrations and through GR activation, aldosterone reduced glucose uptake in adipocytes. Insulin resistance in primary aldosteronism might occur in compartments other than fat and/or depend on concurrent environmental factors.

[Gitelman syndrome associated with chondrocalcinosis: description of two cases]

Gitelman syndrome is a rare inherited tubulopathy, characterized by hypomagnesemia, hypokalemia, metabolic alkalosis, hypocalciuria and hyperreninemic hyperaldosteronism. The clinical spectrum is wide and includes: cramps, myalgias, muscle weakness, until episodes of carpo-podalic spasm, tetania, rhabdomyolysis and paralysis. Some cases have been described in literature underlining the association of this condition with chondrocalcinosis, as a typical example of hypomagnesemia-induced crystal deposition disease. The therapy of Gitelman syndrome consists on the administration of defective electrolytes, although not always effective. We describe two cases of Gitelman syndrome associated with chondrocalcinosis showing the wide range of presentation of this clinical condition.

Metabolic syndrome in primary aldosteronism and essential hypertension: relationship to adiponectin gene variants

BACKGROUND AND AIMS

Evidence shows that aldosterone excess is crucial for the development of cardiac and metabolic complications. Among the possible pathogenetic elements of the metabolic syndrome, adiponectin and its polymorphisms seem to confer a genetic risk for metabolic alterations and type 2 diabetes. Aims of the study were to investigate whether metabolic syndrome represents a common feature in patients with primary aldosteronism (PA) compared with essential hypertensives (EH) and to study the impact of two common adiponectin gene variants on the parameters of metabolic syndrome.

METHODS AND RESULTS

Metabolic syndrome was defined according to ATPIII criteria. Eighty-nine patients with PA and 164 matched EH were studied. In all patients with PA and in 135 EH two single nucleotide polymorphisms of the adiponectin gene, T45G and G276T, were detected. Patients with PA displayed a higher prevalence of metabolic syndrome compared with EH (45% vs. 30%, p<0.05). In patients with PA, genotypes 45T/G+G/G were associated with significantly lower values of waist circumference, HOMA-IR and serum aldosterone. In both PA patients and EH, the 276T/T genotype was associated with significantly worse metabolic profile and a higher risk for the metabolic syndrome (OR=1.5 for PA and OR=1.3 for EH).

CONCLUSIONS

Our data confirm a higher prevalence of metabolic syndrome among patients with PA compared with matched EH. Genetic analysis of T45G and G276T adiponectin gene polymorphisms showed that, while the genotypes 45G/G+G/T seemed to have a protective role on the metabolic complications, the genotype 276T/T defined PA and EH patients with a worse metabolic profile.

Within-patient reproducibility of the aldosterone: renin ratio in primary aldosteronism

The plasma aldosterone concentration:renin ratio (ARR) is widely used for the screening of primary aldosteronism, but its reproducibility is unknown. We, therefore, investigated the within-patient reproducibility of the ARR in a prospective multicenter study of consecutive hypertensive patients referred to specialized centers for hypertension in Italy. After the patients were carefully prepared from the pharmacological standpoint, the ARR was determined at baseline in 1136 patients and repeated after, on average, 4 weeks in the patients who had initially an ARR > or =40 and in 1 of every 4 of those with an ARR <40. The reproducibility of the ARR was assessed with Passing and Bablok and Deming regression, coefficient of reproducibility, and Bland-Altman and Mountain plots. Within-patient ARR comparison was available in 268 patients, of whom 49 had an aldosterone-producing adenoma, on the basis of the "4-corner criteria." The ARR showed a highly significant within-patient correlation (r=0.69; P<0.0001) and reproducibility. Bland-Altman plot showed no proportional, magnitude-related, or absolute systematic error between the ARR; moreover, only 7% of the values, for example, slightly more than what could be expected by chance, fell out of the 95% CI for the between-test difference. The accuracy of each ARR for pinpointing aldosterone-producing adenoma patients was approximately 80%. Thus, although it was performed under different conditions in a multicenter study, the ARR showed a good within-patient reproducibility. Hence, contrary to previously claimed poor reproducibility of the ARR, these data support its use for the screening of primary aldosteronism.

Reduced nitric oxide levels in acromegaly: cardiovascular implications

Acromegaly is characterized by major cardiovascular alterations. Although the underlying mechanisms of these vascular modifications have not been elucidated, recent studies have focused on endothelial dysfunction. Nitric oxide (NO) may contribute to increased vascular resistance, reduced platelet aggregation, inhibition of smooth muscle cell proliferation, and reduction of lipoxygenase activity. At present, no data on NO production in acromegalics are available. The aim of this study was to evaluate the effect of high levels of growth hormone (GH) and insulin-like growth factor-1 (IGF-1) present in acromegaly on NO pathway to investigate the role played by this molecule in the cardiovascular changes experienced by these patients. We studied 13 acromegalics and 12 sex- and age-matched normotensive controls. Platelet NO levels were measured in the supernatant of lysed platelets. Endothelial NO synthase (eNOS) was determined by Western blot analysis of platelets. NO concentrations were significantly reduced in patients (p<0.0001). There were no differences between male and female patients, nor were platelet NO levels and the presence/absence of hypertension related in acromegalics; by contrast, NO concentrations inversely correlated with GH (p=0.03) and IGF-1 (p=0.04) levels, and with disease duration (p=0.04). eNOS protein concentrations were significantly reduced in the platelets of patients compared with controls (p<0.0001). This study demonstrates for the first time a strong reduction in platelet NO concentrations in acromegalic patients due to reduced eNOS expression. Moreover the inverse correlation of NO levels with GH, IGF-1 and disease duration suggests that reduced levels of platelet NO linked to GH excess may contribute to the vascular alterations affecting patients with acromegaly.

Clinically guided genetic screening in a large cohort of italian patients with pheochromocytomas and/or functional or nonfunctional paragangliomas

PURPOSE

The aim of the study was to define the frequency of hereditary forms and the genotype/phenotype correlations in a large cohort of Italian patients with pheochromocytomas and/or functional or nonfunctional paragangliomas.

DESIGN

We examined 501 consecutive patients with pheochromocytomas and/or paragangliomas (secreting or nonsecreting). Complete medical and family histories, as well as the results of clinical, laboratory, and imaging studies, were recorded in a database. Patients were divided into different groups according to their family history, the presence of lesions outside adrenals/paraganglia considered syndromic for VHL disease, MEN2, and NF1, and the number and types of pheochromocytomas and/or paragangliomas. Germ-line mutations in known susceptibility genes were investigated by gene sequencing (VHL, RET, SDHB, SDHC, SDHD) or diagnosed according to phenotype (NF1). In 160 patients younger than 50 yr with a wild-type profile, multiplex ligation-dependent probe amplification assays were performed to detect genomic rearrangements.

RESULTS

Germline mutations were detected in 32.1% of cases, but frequencies varied widely depending on the classification criteria and ranged from 100% in patients with associated syndromic lesions to 11.6% in patients with a single tumor and a negative family history. The types and number of pheochromocytomas/paragangliomas as well as age at presentation and malignancy suggest which gene should be screened first. Genomic rearrangements were found in two of 160 patients (1.2%).

CONCLUSIONS

The frequency of the hereditary forms of pheochromocytoma/paraganglioma varies depending on the family history and the clinical presentation. A positive family history and an accurate clinical evaluation of patients are strong indicators of which genes should be screened first.

Small tumor size as favorable prognostic factor after adrenalectomy in Conn's adenoma

OBJECTIVE

Primary aldosteronism (PA) due to aldosterone-producing adenoma (APA) is the most common curable form of secondary hypertension.

DESIGN

In order to evaluate blood pressure outcome after adrenalectomy for APA and to identify new favorable prognostic factors, data from 42 consecutive APA patients who underwent adrenalectomy were collected from 2005 to 2007.

METHODS

Renin-angiotensin-aldosterone system (upright and postsaline infusion test), serum and urinary electrolytes, office and ambulatory blood pressure monitoring were evaluated at baseline and after a follow-up of 2.7+/-2.2 years. Drug history and adenoma size at morphological evaluation were also collected.

RESULTS

Multiple regression analysis showed that, before surgery, patients with a small adenoma (diameter <20 mm) displayed higher postsaline aldosterone values (P=0.0001), and lower serum potassium levels (P=0.020), than patients with adenoma >20 mm. Before surgery, mineralocorticoid receptor (MR) antagonists were used in patients with small APA in greater percentage than patients with bigger adenomas (64 vs 30% respectively, P=0.037). At follow-up, blood pressure normalized in 63% of the subjects. Recovered patients had a shorter duration of hypertension (P=0.038), and a smaller adenoma size (P=0.035). Receiver operating characteristic curves showed that a duration of hypertension <or=6 years and an APA size <20 mm were the best predictors of blood pressure normalization. Patients with APA <20 mm showed the complete restoration of blood pressure circadian rhythm.

CONCLUSIONS

The presence of APA <20 mm, duration of hypertension equal or less than 6 years, and preoperative MR antagonists use are favorable prognostic factors for hypertension recovery after adrenalectomy.

Management of primary aldosteronism: its complications and their outcomes after treatment

Primary aldosteronism is the most common cause of secondary hypertension, accounting for about 10% of all forms of high blood pressure. Life-time pharmacological therapy is the treatment of choice for primary aldosteronism due to idiopathic adrenal hyperplasia (IHA), while adrenalectomy is effective in curing most patients with an aldosterone producing adenoma (APA). Far from being a benign form of hypertension, primary aldosteronism is characterized by the development of cardiovascular renal and metabolic complications, including left ventricular hypertrophy, myocardial infarction, atrial fibrillation and stroke, microalbuminuria, renal cysts as well as metabolic syndrome, glucose impairment and diabetes mellitus. We review recent clinical experience with the above mentioned complications and long-term outcomes of blood pressure normalization and cardiac, renal and gluco-metabolic complications in patients with primary aldosteronism, after medical treatment with mineralocorticoid receptor antagonists and surgical treatment. We conclude that removal of adrenal adenoma results in normalization of the renin-angiotensin-aldosterone system (RAAS) and of kalaemia and improvement of blood pressure levels in all patients. Complete resolution of hypertension is achieved in nearly half of treated patients. Moreover, unilateral adrenalectomy is the best treatment to have the regression of cardiovascular, renal and metabolic complications in patients with APA. On the other hand, targeted medical treatment with aldosterone antagonists improves blood pressure control and appears able to prevent the progression of cardiac and metabolic complications in patients with IHA.

Long-term results of laparoscopic adrenalectomy for primary aldosteronism

BACKGROUND

The management of primary aldosteronism is currently achieved by both medical and surgical treatment. Laparoscopy has in recent years unquestionably become the gold standard in adrenal surgery for benign lesions. This study aims to evaluate our clinical results among patients who underwent laparoscopic adrenalectomy (LA) for primary aldosteronism.

METHODS

From January 1994 to January 2006, amid LA series, 59 primary aldosteronism patients were treated in our institution. Patients were 33 males and 26 females with mean age 49.3 yr (19-78). The mean body mass index was 25.9 kg/m2 (20.5-33.3). The mean size of lesion was 2.9 cm (1-5.5). Clinical symptoms were as follows: hypertension and symptomatic/asymptomatic hypokalemia (54), hypokalemia (5).

RESULTS

Thirty-five left and 24 right LA were performed. On the left side, 22 procedures were carried out by anterior approach, 9 by anterior submesocolic route, and 4 by means of flank approach. All right procedures were completed by the anterior supine approach. The mean operative time was 103.5 min for left and 92.8 min for right adrenalectomy. There was one major complication, a colonic post-operative fistula, regarding a left adrenalectomy case. The mean post-operative hospital stay was 3 days (1-9). The cure rate of hypertension and hypokalemia was similar to the current literature results.

CONCLUSIONS

LA is a safe and effective option in the treatment of primary aldosteronism. Appropriate selection of patients, larger adrenal masses and duration of symptoms are determining factors in the success rate of hypertension management.

Changes in adenosine 5'-monophosphate-activated protein kinase as a mechanism of visceral obesity in Cushing's syndrome

OBJECTIVE

Features of the metabolic syndrome such as central obesity with insulin resistance and dyslipidemia are typical signs of Cushing's syndrome and common side effects of prolonged glucocorticoid treatment. AMP-activated protein kinase (AMPK), a key regulatory enzyme of lipid and carbohydrate metabolism as well as appetite, is involved in the development of the deleterious metabolic effects of excess glucocorticoids, but no data are available in humans. In the current study, we demonstrate the effect of high glucocorticoid levels on AMPK activity of human adipose tissue samples from patients with Cushing's syndrome.

METHODS

AMPK activity and mRNA expression of genes involved in lipid metabolism were assessed in visceral adipose tissue removed at abdominal surgery of 11 patients with Cushing's syndrome, nine sex-, age-, and weight-matched patients with adrenal incidentalomas, and in visceral adipose tissue from four patients with non-endocrine-related abdominal surgery.

RESULTS

The patients with Cushing's syndrome exhibited a 70% lower AMPK activity in visceral adipose tissue as compared with both incidentalomas and control patients (P = 0.007 and P < 0.001, respectively). Downstream targets of AMPK fatty acid synthase and phosphoenol-pyruvate carboxykinase were up-regulated in patients with Cushing's syndrome. AMPK activity was inversely correlated with 0900 h serum cortisol and with urinary free cortisol.

CONCLUSIONS

Our data suggest that glucocorticoids inhibit AMPK activity in adipose tissue, suggesting a novel mechanism to explain the deposition of visceral adipose tissue and the consequent central obesity observed in patients with iatrogenic or endogenous Cushing's syndrome.

Polymorphisms of EDNRB, ATG, and ACE genes in salt-sensitive hypertension

Almost 50% of hypertensive individuals manifest blood pressure changes in response to salt depletion or repletion and are termed "salt sensitive" (SS). Blunted activity of the endothelin (ET) system and the renin-angiotensin-aldosterone system (RAAS) have been reported as possible mechanisms contributing to salt sensitivity. Data are available that endothelin receptor subtype B (ETBR)-deficient rats develop salt-sensitive hypertension when fed a high-salt diet. Whether the ETBR gene (EDNRB) is involved in genetic predisposition to human salt-sensitive hypertension has not been studied so far. We screened EDNRB in 104 hypertensive patients (49 salt sensitive and 55 salt resistant) and 110 normotensive controls. No new sequence variation was found, but genotype distribution of the common polymorphism G1065A revealed that the AA + GA genotypes were significantly more frequent in salt-resistant than in salt-sensitive individuals (p = 0.007), suggesting a protective role for the A allele. We also screened angiotensinogen gene AGT M235T and angiotensin-converting enzyme insertion/deletion polymorphism ACE I/D and found an association between TT genotype and hypertension. A possible synergistic effect to salt-sensitive hypertension was found by combining EDNRB GG with ACE DD/ID genotypes. In conclusion, our data confirm the role of ET system and RAAS in salt-sensitive hypertension.

Diagnosis and management of primary aldosteronism

PURPOSE OF REVIEW

To illustrate the steps for clinical management of primary aldosteronism from screening evaluation to surgical and/or medical treatment.

RECENT FINDINGS

It is now widely accepted that primary aldosteronism represents the most common form of endocrine hypertension and its early diagnosis is crucial for hypertensive patients who can be cured by the surgical removal of an aldosterone-secreting adenoma or benefit from a specific medical treatment with mineralocorticoid receptor antagonists. Recent evidence indicates that hyperaldosteronism is indeed associated with detrimental consequences on cardiovascular system, renal function and glucose metabolism.

SUMMARY

The diagnostic protocol for primary aldosteronism requires multistep evaluation and should begin with a screening test, followed when appropriate, by confirmatory test and functional and anatomical evaluation. Finally, although it is technically difficult and the cut-off levels for acceptance of the success are not standardized, the subtype forms should be identified using a selective adrenal venous sampling.

Body mass index predicts plasma aldosterone concentrations in overweight-obese primary hypertensive patients

CONTEXT

Body mass index (BMI) shows a direct correlation with plasma aldosterone concentration (PAC) and urinary aldosterone excretion in normotensive individuals; whether the same applies to hypertensive patients is unknown.

OBJECTIVE

Our objective was to determine if BMI predicts PAC and the PAC/plasma renin activity ratio [aldosterone renin ratio (ARR)] in hypertensive patients, and if this affects the identification of primary aldosteronism (PA).

DESIGN

This was a prospective evaluation of consecutive hypertensive patients referred nationwide to specialized hypertension centers.

MAIN OUTCOME MEASURES

Sitting PAC, plasma renin activity, and the ARR, baseline and after 50 mg captopril orally with concomitant assessment of parameters, including BMI and daily sodium intake, were calculated.

RESULTS

Complete biochemical data and a definite diagnosis were obtained in 1125 consecutive patients. Of them 999 had primary (essential) hypertension (PH) and 126 (11.2%) PA caused by an aldosterone-producing adenoma in 54 (4.8%). BMI independently predicted PAC (beta = 0.153; P < 0.0001) in PH, particularly in the overweight-obese, but not in the PA group. Covariance analysis and formal comparison of the raw, and the BMI-, sex-, and sodium intake-adjusted ARR with receiver operator characteristic curves, showed no significant improvement for the discrimination of aldosterone-producing adenoma from PH patients with covariate-adjusted ARR.

CONCLUSIONS

BMI correlated with PAC independent of age, sex, and sodium intake in PH, but not in PA patients. This association of BMI is particularly evident in overweight-obese PH patients, and suggests a pathophysiological link between visceral adiposity and aldosterone secretion. However, it does not impact on the diagnostic accuracy of the ARR for discriminating PA from PH patients.

Adipose cell-adrenal interactions: current knowledge and future perspectives

The central role of adipose tissue in the development of cardiovascular and metabolic pathology has been highlighted by the discovery of mediators (adipokines) secreted by adipose tissue and their involvement in the regulation of various biological processes. In light of recent experimental data, cross-talk between adipose tissue and the adrenal gland, particularly via the mineralocorticoid aldosterone, has been proposed. Aldosterone can induce adipogenesis, and human white adipose tissue is reported to release as-yet-uncharacterized factors that stimulate adrenocortical steroidogenesis and aldosterone production. These data could provide new insights into the pathophysiology of obesity-related disorders, including hypertension and aldosterone excess, with further studies necessary for confirming and better defining such adipose-adrenal interactions.

Primary aldosteronism: cardiovascular, renal and metabolic implications

For many years primary aldosteronism was considered a relatively benign form of hypertension. This assumption reflects the primacy accorded to elevated levels of angiotensin in terms of deleterious cardiovascular effects, and the fact that in primary aldosteronism renin and angiotensin levels are low. We now know that primary aldosteronism causes a constellation of cardiovascular, renal and metabolic sequelae which make it far from benign and that these are not merely effects of blood pressure elevation. In primary aldosteronism, tissue damage, on several indices, is higher than in age-, sex- and blood pressure-matched controls, reflecting the ability of inappropriately elevated aldosterone for salt status to produce structural and functional changes over and above those produced by high blood pressure.

Primary aldosteronism, a major form of low renin hypertension: from screening to diagnosis

There is general consensus on the use of (but not cut-off values for) the aldosterone/plasma renin activity ratio as a screening test for primary aldosteronism. There is also agreement on the need for subsequent confirmatory testing, but not on the protocols to be chosen. The four most common confirmatory tests in clinical practice are oral sodium loading, intravenous saline infusion, captopril challenge and fludrocortisone administration plus sodium loading. The choice of test reflects multiple variables: patient factors (including accessibility, compliance and safety), established practice and cost. Finally, subtype forms and lateralization of aldosterone production should be established by bilateral adrenal venous sampling, despite its technical difficulty and varying criteria for success.