Salt intake in mineralocorticoid receptor antagonist-treated primary aldosteronism: foe or ally?

Mild hyperkalemia is a common side effect of mineralocorticoid receptor antagonist (MRA) treatment of patients with primary aldosteronism (PA), which can be worsened by instructions to minimize salt intake. Our objective was to evaluate the effect of salt consumption on serum potassium levels and mean, mean minimal, and mean maximal systolic and diastolic blood pressure (BP) in MRA-treated hyperkalemic PA patients under relative salt restriction. Seventeen consecutive mildly hyperkalemic MRA-treated PA patients aged 66.3 ± 8.37 years were recruited. Body mass index (BMI) and BP were assessed, and serum and 24-h urinary sodium and potassium levels, plasma renin, and serum aldosterone were measured, while patients followed a relatively salt-restricted diet, after 1 month of controlled salt supplementation (usual salt-restricted diet plus 4 g salt/day) and after 6 months on instructions for free dietary salt consumption. Baseline salt consumption was additionally evaluated in two more patient groups (normotensive subjects and normokalemic MRA-treated PA patients). One month of controlled salt supplementation (24-h urine sodium (median, min, max): 195.2 (120.30-275.20) vs 110.13 (34.30-139.20) mEq/day, p < 0.001) resulted in increased kaliuresis (62.25 (40.69-97.0) vs 54.0 (23.28-79.60) mEq/day, p = 0.001) and a decrease of serum potassium (5.2 (5-5.70) vs 4.6 (3.8-5.1) mEq/L, p < 0.001), while serum sodium (139 (133-141) vs 1 39 (135-144) mEq/L) and mean systolic (130 (105-141 vs. 130 (106-141) mmHg) and diastolic (76 (53-85) vs75 (53-84) mmHg) BP remained stable. These findings were unchanged after 6 months of free salt consumption. BMI remained constant, while plasma renin and serum aldosterone decreased following salt repletion. Adequate salt consumption attenuates MRA-induced hyperkalemia in relatively salt-restricted PA patients without affecting BP or BMI.

Adrenal disorders and non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in the developed world and its pathogenesis is complex and multifactorial. It is considered the hepatic manifestation of the metabolic syndrome and is the leading cause of hepatic cirrhosis. This review aims to present current knowledge on the involvement of the adrenal glands in the development of NAFLD. Clinical and animal studies have shown that excess glucocorticoids (GC) have been implicated in the pathogenesis of NAFLD. Patients with NAFLD seem to have a subtle chronic activation of the hypothalamic pituitary adrenal axis leading to a state of subclinical hypercortisolism. Regulators of GC such as 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1), an enzyme that regenerates cortisol from inactive cortisone, and 5α/5ß-reductases, enzymes that increase cortisol clearance, are implicated in the development of NAFLD by amplifying local GC action. Adrenal androgen (dehydroepiandrosterone) abnormalities and increased aldosterone levels may also have a role in the development of NAFLD whereas the contribution of adrenergic signaling in NAFLD pathogenesis remains unclear.

Concomitant alterations of metabolic parameters, cardiovascular risk factors and altered cortisol secretion in patients with adrenal incidentalomas during prolonged follow-up.

OBJECTIVE: Adrenal incidentalomas (AI) are associated with metabolic and hormonal abnormalities, most commonly autonomous cortisol secretion (ACS). Data regarding alterations of insulin resistance (IR) and ACS after prolonged follow-up are limited. We investigated the evolution of IR, cortisol secretion and ACS development in patients with AI during prolonged follow-up. DESIGN: Prospective study in a tertiary hospital. PATIENTS AND MEASUREMENTS: Seventy-one patients with AI [51 nonfunctioning (NFAI) and 20 ACS] and 5·54 ± 1·7 years follow-up underwent testing for ACS and oral glucose tolerance test to determine IR indices and adrenal imaging. RESULTS: At follow-up, 16/51 (31%) NFAI patients converted to ACS, while two with previous ACS reverted to NFAI; 21% (7/33) of patients who did not covert to ACS exhibited high urinary-free cortisol (H-UFC) levels. All AI patients developed deterioration of IR irrespective of their cortisol secretory status. Eight patients developed newly diagnosed type 2 diabetes (9·8% NFAI and 15% ACS, respectively) and 14 IR (17·6% NFAI and 25% ACS, respectively). Adenoma size increased from 2·1 ± 0·8 to 2·3 ± 0·8 cm, whereas IR correlated with postdexamethasone cortisol level and adenoma size increase. IR showed an incremental continuum trend from normal UFC (Ν-UFC), to H-UFC, C-ACS and ACS patients. CONCLUSIONS: New-onset ACS developed in 31% patients with NFAI, whereas 21% of NFAI patients had H-UFC levels. All AI patients as a group and the subgroups of N-UFC, H-UFC, C-ACS and ACS patients developed deterioration of metabolic parameters during follow-up that was more prominent in ACS patients.

Identification of a novel mutation of the PRKAR1A gene in a patient with Carney complex with significant osteoporosis and recurrent fractures.

OBJECTIVE: Carney complex (CNC) is a rare autosomal dominant multiple neoplasia syndrome characterized by the presence of endocrine and non-endocrine tumors. More than 125 different germline mutations of the protein Kinase A type 1-α regulatory subunit (PRKAR1A) gene have been reported. We present a novel PRKAR1A gene germline mutation in a patient with severe osteoporosis and recurrent vertebral fractures. DESIGN: Clinical case report. CASE REPORT: A 53-year-old male with a medical history of surgically removed recurrent cardiac myxomas was evaluated for repeated low-pressure vertebral fractures and severe osteoporosis. Physical examination revealed spotty skin pigmentation of the lower extremities and papules in the nuchal and thoracic region. The presence of hypercortisolism due to micronodular adrenal disease and the history of cardiac myxomas suggested the diagnosis of CNC; the patient underwent detailed imaging investigation and genetic testing. METHODS: Standard imaging and clinical testing; DNA was sequenced by the Sanger method. RESULTS: Sequence analysis from peripheral lymphocytes DNA revealed a novel heterozygous point mutation at codon 172 of exon 2 (c.172G>T) of the PRKAR1A gene, resulting in early termination of the PRKAR1A transcript [p.Glu58Ter (E58X)]. CONCLUSION: We report a novel point mutation of the PRKAR1A gene in a patient with CNC who presented with significant osteoporosis and fractures. Low bone mineral density along with recurrent myxomas should point to the diagnosis of CNC.

Urinary clonidine suppression testing for the diagnosis of pheochromocytoma.

OBJECTIVE: The diagnosis of pheochromocytoma/paraganglioma (PPGL) involves detection of elevated levels of plasma and/or 24-h urine catecholamines and/or their metabolites, including metanephrines. Although these tests are reasonably sensitive, false-positive results are often encountered. Follow-up tests can provide additional information to correctly diagnose PPGL. In this regard, the utility of the urinary clonidine suppression test (UCST) remains unknown. METHODS: To assess the diagnostic accuracy of the UCST in confirming or excluding PPGL, we conducted a retrospective analysis of all patients who underwent a UCST between 2000 and 2013 (n = 59; 15 PPGLs) at a single centre. Twelve-hour urine catecholamines and metanephrines were assessed before and after clonidine administration, and examined in relation to final diagnosis, PPGL or non-PPGL. Receiver operating characteristic analyses were used to identify optimal positivity cut-offs. Sensitivity, specificity, positive and negative predictive values were calculated. RESULTS: Clonidine significantly decreased urine creatinine-corrected norepinephrine and normetanephrine in patients without PPGL (P < 0.001 pairwise) but not in patients with PPGL. Epinephrine and metanephrine levels were not significantly reduced in either group. Receiver operating characteristic (ROC) area under the curve was 0.955 [95% confidence interval (95% CI) 0.906-1.000, P < 0.001] and 0.823 (95% CI 0.706-0.940, P < 0.001) for norepinephrine and normetanephrine, respectively. Optimal cut-offs were established at 50 and 15% reductions in norepinephrine and normetanephrine, respectively, which provided high sensitivities (93.3% for both) and negative predictive values (97.4 and 96.3%). When both were concordant, higher diagnostic accuracy was achieved (100% sensitivity, 92.0% specificity). Results were similar in subgroups of individuals with borderline initial testing (n = 40) or on interfering drugs (n = 25). CONCLUSION: The UCST appears to be a highly accurate test for PPGL. Further prospective studies are needed to validate these results before routine use is encouraged.

Impact and duration effect of telemonitoring on ΗbA1c, BMI and cost in insulin-treated Diabetes Mellitus patients with inadequate glycemic control: A randomized controlled study.

OBJECTIVE: To monitor and control the blood glucose levels in inefficiently insulin-treated patients with type 1 and 2 diabetes mellitus (DM) using a telemonitoring system and determine whether the improvement of HbA1c has a lasting effect following its discontinuation. DESIGN: Seventy inefficiently controlled insulin-treated DM patients using telemonitoring (telemonitoring group-TG) [HbA1c 9.9±2.3% (85±24.9mmol/mol)] and 35 age-, body mass index (BMI)- and Hba1c-matched insulin-treated patients receiving outpatient care (control group-CG) [HbA1c 9.7±2.1% (82±23.4mmol/mol)] were enrolled. Data of TG were transmitted from the glucose-meters to our computers via modem. Communication was achieved via e-mails and mobile phone text-messages through integrated software. HbA1c and BMI were evaluated at enrollment, 3 and 6 months, and 6 months after telemonitoring discontinuation. Frequency of hypo- and hyperglycemias and cost were also analyzed. RESULTS: Significant reduction in HbA1c was observed in TG both at 3 [7.1±1.0% (54±10.5mmol/mol) p<0.001] and 6 months [6.9±0.9% (52±9.5mmol/mol) p<0.001], compared to the CG group at the same timepoints. Significant reduction was also observed in the TG subgroups with ΗbA1c≥10% and 10>HbA1c≥7.5% at 3 and 6 months, compared to CG. No statistically significant differences in BMI were observed between TG and CG. Six months after telemonitoring discontinuation, HbA1c in TG was slightly increased [7.3±1.0% (56±10.4mol/mol)]. Attenuation was also observed in both TG subgroups. Compared to CG, the number of monthly hypo- and hyperglycemias was reduced in TG. The intervention had a financial benefit for patients living more than 100 km from the health care provider. CONCLUSIONS: Telemonitoring can result in reduction of HbA1c and frequency of hypo- and hyperglycemias. This beneficial effect is slightly attenuated 6 months after terminating telemonitoring.

Stress-induced Aldosterone Hyper-Secretion in a Substantial Subset of Patients With Essential Hypertension.

CONTEXT: Aldosterone (ALD) secretion is regulated mainly by angiotensin II, K(+), and adrenocorticotropic hormone (ACTH). Mineralocorticoid receptor antagonists (MRAs) have effectively been used for the treatment of patients with hypertension who do not have primary aldosteronism (PA). OBJECTIVE: We tested whether chronic stress-related ACTH-mediated ALD hypersecretion and/or zona glomerulosa hypersensitivity could be implicated in the pathogenesis of essential hypertension (ESHT). PATIENTS AND METHODS: One hundred thirteen hypertensives without PA and 61 normotensive controls underwent an ultralow-dose (0.03-µg) ACTH stimulation and a treadmill test. Patients with ALD hyper-response according to the cutoffs obtained from controls received treatment with MRAs and underwent genomic DNA testing for the presence of the CYP11B1/CYP11B2 chimeric gene and KCNJ5 gene mutations. A control group of 22 patients with simple ESHT received treatment with MRAs. RESULTS: Based on the cutoffs of ALD and aldosterone-to-renin ratio (ARR) post-ACTH stimulation obtained from controls, 30 patients (27%) exhibited an ALD but not cortisol (F) hyper-response (HYPER group). This group had no difference in basal ACTH/renin (REN) concentrations compared with controls and the 83 patients with hypertension (73%) without an ALD hyper-response to ACTH stimulation. Patients in the HYPER group demonstrated significantly higher ALD concentrations, ARR, and ALD/ACTH ratio (AAR) in the treadmill test. Treatment with MRAs alone produced normalization of blood pressure in these patients whereas patients with hypertension with neither PA nor ALD hyper-response to ACTH stimulation who served as a control group failed to lower blood pressure. Also, two novel germline heterozygous KCNJ5 mutations were detected in the HYPER group. CONCLUSIONS: A number of patients with hypertension without PA show ACTH-dependent ALD hyper-secretion and benefit from treatment with MRAs. This could be related to chronic stress via ACTH hyper secretion and/or gene-mutations increasing the zona glomerulosa responsiveness to excitatory stimuli.

Reversal of impaired counterregulatory cortisol response following diazoxide treatment in a patient with non insulinoma pancreatogenous hypoglycemia syndrome: Case report and overview of pathogenetic mechanisms.

OBJECTIVE: Non-insulinoma pancreatogenous hypoglycemia syndrome (NIPHS) is one of the rare causes of endogenous hyperinsulinism. Its diagnosis is challenging and may require selective intraarterial calcium stimulation and concomitant hepatic vein sampling (SACVS). Impaired counterregulatory hormones' production in response to hypoglycemia has been previously described in patients with diabetes, insulinoma and infancy hypoglycemia. We present a case of endogenous hyperinsulinism, secondary to NIPHS, with deficient cortisol response to hypoglycemia which resolved after diazoxide treatment. DESIGN-RESULTS: A 43-year-old woman was admitted with recurrent episodes of registered fasting and postprandial hypoglycemia. Abdominal computed tomography, magnetic resonance imaging and endoscopic ultrasonography of the pancreas failed to reveal any lesion while SACVS sampling demonstrated a 5- to 8-fold increase in insulin levels in diverse parts of the pancreas. Counterregulatory hormones' measurement revealed an attenuated cortisol response. Treatment with diazoxide resulted in disappearance of hypoglycemic episodes. Twelve months later, an insulin tolerance test was performed which revealed a normal cortisol response. CONCLUSIONS: This report describes the first, to our knowledge, reported case in the literature of NIPHS with deficient cortisol response to hypoglycemia which resolved after diazoxide treatment. It is important for clinicians to include NIPHS in the differential diagnosis of hypoglycemia and identify possible impairment of counterregulatory hormones' production.

Primary aldosteronism in hypertensive patients: clinical implications and target therapy.

BACKGROUND: The prevalence of primary aldosteronism (PA) in hypertensive patients varies according to diagnostic testing and ascertained normal cut-offs. The aim of this case-control study was to confirm the high prevalence of PA in a large hypertensive population and evaluate the antihypertensive effect of mineralocorticoid receptor antagonists (MRA) treatment. MATERIAL AND METHODS: We investigated 327 hypertensive and 90 matched normotensive subjects with normal adrenal imaging. Serum aldosterone (ALD), active renin (REN) levels and aldosterone/active renin (ALD/REN) ratio were measured before and after a combined sodium chloride, fludrocortisone and dexamethasone suppression test (FDST). Post-FDST values were compared to cut-offs obtained from controls (post-FDST ALD 2·96 ng/dL and post-FDST ALD/REN 0·93 ng/dL/µU/mL). PA patients received MRA treatment. RESULTS: By applying the combination of post-FDST ALD levels and ALD/REN ratio, 28·7% of the hypertensive patients had PA. There was a positive, albeit weak, correlation between systolic (SBP) and diastolic blood pressure (DBP) and ALD levels and/or ALD/REN ratio after the FDST (P < 0·0001). SBP was associated with a post-FDST ALD of 3·24 ng/dL and ALD/REN ratio of 0·90 ng/dL/µU/mL, whereas post-FDST ALD had an inverse association at serum K+ values of less than 3·9 mEq/L. MRA treatment in 69 PA patients, resulted in a significant reduction in the maximum SBP and DBP values (28 ± 15 and 14 ± 7 mmHg, respectively, P < 0·0001). CONCLUSIONS: Using the FDST, an increased prevalence of PA in hypertensives was observed. Α significant blood pressure lowering effect was obtained with MRA treatment, implying that these agents may be beneficial in a significant number of hypertensive patients.

Brain and optic chiasmal herniation following cabergoline treatment for a giant prolactinoma: wait or intervene?

OBJECTIVE: Dopamine agonists (DA) are the treatment of choice in patients with macroprolactinomas. Brain and optic chiasm herniation are unusual complications following treatment with DA. REPORT: We present a case of a giant prolactinoma complicated by visual deterioration following cabergoline treatment. A 42-year-old man was admitted with seizures, right visual loss and visual defect in the upper left temporal quadrant. Magnetic resonance imaging (MRI) identified a giant adenoma, which proved to be a prolactinoma, compressing the optic chiasm and extending into the suprasellar region. Treatment with cabergoline was initiated resulting in improvement in visual fields, tumor shrinkage and prolactin level decrease. Five months later and despite tumor reduction, a deterioration of his visual fields was observed. The second MRI revealed brain and optic chiasmal herniation into the pituitary sella. Cabergoline dose was reduced and surgical resection of the adenoma along with untethering of the optic nerve was performed leading to improvement of the visual defects. CONCLUSIONS: This report describes a rare case of brain and optic chiasmal herniation attributed to DA therapy for a macroprolactinoma. It is important for clinicians to examine visual fields and promptly identify any visual deterioration in patients with macroprolactinomas receiving DA treatment.

HLA-DR expressing peripheral T regulatory cells in newly diagnosed patients with different forms of autoimmune thyroid disease.

BACKGROUND: Several reports have claimed a role for T regulatory cells (Tregs) in the pathogenesis of various autoimmune diseases, including autoimmune thyroid disease (AITD). The aim of the present study was to examine whether changes in the number of peripheral CD4 + CD25highHLA-DR + lymphocytes, a subpopulation of Tregs, occur in patients with AITD. METHODS: Three-color flow cytometry was used to detect the proportion of CD4 cells expressing CD25, CD25high, and HLA-DR in 70 newly diagnosed and untreated AITD patients and 20 controls. The intensity of CD25 expression on these cells was also examined. RESULTS: The proportion of CD4 + CD25 + cells as well as the proportion of CD4 + CD25high cells among the population of CD4 lymphocytes was not different in AITD patients relative to controls. However, a significant increase in the proportion of CD4 + CD25highHLA-DR + cells among the population of CD4 lymphocytes was found in patients with Hashimoto's thyroiditis (HT) compared to controls. CONCLUSIONS: In HT patients there is a quantitative increase of CD4 + CD25highHLA-DR + cells that may indicate a compensatory expansion of this subpopulation of Tregs in an attempt to suppress the immune response.

Differential expression of Fas system apoptotic molecules in peripheral lymphocytes from patients with Graves' disease and Hashimoto's thyroiditis.

OBJECTIVE: To examine whether the Fas system apoptotic molecules are differentially expressed in Graves' disease (GD) and Hashimoto's thyroiditis (HT), the two opposite phenotypes of autoimmune thyroid disease (AITD). DESIGN: The expression of Fas and Fas ligand (FasL) on peripheral CD4 and CD8 lymphocytes, and non-lymphoid immune cells as well as their soluble forms in serum from untreated patients with GD and HT were evaluated. METHODS: Flow cytometry was performed for the study of peripheral immune cells from 70 newly diagnosed patients with AITD (55 with HT and 15 with GD) and 20 controls. ELISA was used for the measurement of soluble Fas (sFas) in serum samples from a subgroup of 35 AITD patients. RESULTS: An increase in the proportion of CD4 and CD8 cells expressing Fas was found in both GD and HT, albeit with some differences, when compared with controls. Importantly, in GD patients, the intensity of Fas expression on CD4 and CD8 lymphocytes was reduced and sFas levels in serum were simultaneously increased when compared with HT patients and controls. CONCLUSIONS: The Fas system apoptotic molecules appear to be differentially expressed on peripheral lymphocytes in the two opposite phenotypes of AITD.

The role of iodine in the evolution of thyroid disease in Greece: from endemic goiter to thyroid autoimmunity.

The thyroid gland is dependent on dietary iodine for the production of thyroid hormones, normal iodine requirement being about 150-200 microg/day. Long-term deficiency in iodine intake is associated with the development of goiter. When the prevalence of goiter in a population rises above 5-10%, the problem is considered endemic. Greece is a country with a recent history of moderate iodine deficiency, endemic goiter being prevalent in the 1960s in inhabitants of mountainous regions. Despite recognition of the problem, an iodine prophylaxis program was never officially implemented. Instead, "silent iodine prophylaxis" took place during the 1980s and 1990s with Greece's improvement in socioeconomic conditions. This resulted in the elimination of iodine deficiency and a parallel decrease in the prevalence of goiter among schoolchildren in formerly iodine deficient areas. However, the transition from iodine deficiency to iodine sufficiency or excess was followed by the emergence of autoimmune thyroiditis, especially among young girls, indicating that exposure to excess iodine may trigger thyroid autoimmunity. Thus, the modification of an environmental factor, ie dietary iodine, over the last 40 years in Greece has been associated with changes in the phenotypic expression of thyroid disease from endemic goiter to goiter associated with autoimmune thyroiditis.

The protective role of exercise on stress system dysregulation and comorbidities.

The human body, when under threat, elicits a set of neuroendocrine responses, including an increased secretion of glucocorticoids (GCs) and catecholamines from the adrenal gland and the activation of the sympathetic nervous system. These hormonal secretions allow a "fight or flight" response by mobilizing endogenous substrate and inducing a state of insulin resistance in the liver and skeletal muscles. Although the stress response was essential in ancient times to survive physical aggression, this threat has disappeared in our industrialized societies. However, in today's environment, the same stress responses can be elicited by emotional stimuli or professional and social stress. Such psychological stress may be protracted and unrelated to an increased metabolic demand. Thus, the energy mobilized is not used but is stored in visceral fat depots by the combined action of hypercortisolism and hyperinsulinemia. In addition, chronic activation of the stress system causes suppression of the gonadal, growth hormone (GH), and thyroid axes. These metabolic disturbances, in concert, lead to the clinical expression of a number of comorbidities including central obesity, hypertension, dyslipidemia, and endothelial dysfunction, all components of the metabolic syndrome and cardiometabolic risk factors. Moreover, chronic stress has deleterious effects on the brain and, in particular, affects hippocampal structure and function leading to cognitive and mood disturbances. Importantly, this stress-induced clinical phenotype is likely to be exaggerated in the presence of physical inactivity, resulting in a "stress-induced/exercise deficient" phenotype. Assuming that the stress response is a neuroendocrine mechanism that occurs in anticipation of physical action, then physical activity should be the natural means to prevent the consequences of stress. Indeed, accumulating evidence documents the beneficial effects of regular exercise in preventing or ameliorating the metabolic and psychological comorbidities induced by chronic stress. These benefits are thought to derive from a central effect of exercise to reduce the sensitivity to stress and also peripheral actions influencing metabolic functions and, in particular, insulin sensitivity and the partitioning of fuels toward oxidation rather than storage. It is concluded that chronic psychosocial stress, in the presence of physical inactivity, is likely to contribute to the epidemic of cardiometabolic and emotional disease of our current society. The way to prevent and combat this burden is by regular exercise.