Katharina Lang

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.

KCNJ5 Mutations in European Families With Nonglucocorticoid Remediable Familial Hyperaldosteronism

Primary aldosteronism is the most frequent cause of endocrine hypertension. Three forms of familial hyperaldosteronism (FH) have been described, named FH-I to -III. Recently, a mutation of KCNJ5 has been shown to be associated with FH-III, whereas the cause of FH-II is still unknown. In this study we searched for mutations in KCNJ5 in 46 patients from 21 families with FH, in which FH-I was excluded. We identified a new germline G151E mutation in 2 primary aldosteronism–affected subjects from an Italian family and 3 somatic mutations in aldosterone-producing adenomas, T158A described previously as a germline mutation associated with FH-III, and G151R and L168R both described as somatic mutations in aldosterone-producing adenoma. The phenotype of the family with the G151E mutation was remarkably milder compared with the previously described American family, in terms of both clinical and biochemical parameters. Furthermore, patients with somatic KCNJ5 mutations displayed a phenotype indistinguishable from that of sporadic primary aldosteronism. The functional characterization of the effects of the G151E mutation in vitro showed a profound alteration of the channel function, with loss of K+ selectivity, Na+ influx, and membrane depolarization. These alterations have been postulated to be responsible for voltage gate Ca2+ channel activation, increase in cytosolic calcium, and stimulation of aldosterone production and adrenal cell proliferation. In conclusion, we describe herein a new mutation in the KCNJ5 potassium channel associated with FH-III, responsible for marked alterations of channel function but associated with a mild clinical and hormonal phenotype.

Adrenal Venous Sampling Evaluation of the German Conn's Registry

In patients with primary aldosteronism, adrenal venous sampling is helpful to distinguish between unilateral and bilateral adrenal diseases. However, the procedure is technically challenging, and selective bilateral catheterization often fails. The aim of this analysis was to evaluate success rate in a retrospective analysis and compare data with procedures done prospectively after introduction of measures designed to improve rates of successful cannulation. Patients were derived from a cross-sectional study involving 5 German centers (German Conns registry). In the retrospective phase, 569 patients with primary aldosteronism were registered between 1990 and 2007, of whom 230 received adrenal venous sampling. In 200 patients there were sufficient data to evaluate the procedure. In 2008 and 2009, primary aldosteronism was diagnosed in 156 patients, and adrenal venous sampling was done in 106 and evaluated prospectively. Retrospective evaluation revealed that 31% were bilaterally selective when a selectivity index (cortisol adrenal vein/cortisol inferior vena cava) of ≥2.0 was applied. Centers completing <20 procedures had success rates between 8% and 10%. Overall success rate increased in the prospective phase from 31% to 61%. Retrospective data demonstrated the pitfalls of performing adrenal venous sampling. Even in specialized centers, success rates were poor. Marked improvements could be observed in the prospective phase. Selected centers that implemented specific measures to increase accuracy, such as rapid-cortisol-assay and introduction of standard operating procedures, reached success rates of >70%. These data demonstrate the importance of throughput, expertise, and various potentially beneficial measures to improve adrenal vein sampling.

High Incidence of Adrenal Crisis in Educated Patients With Chronic Adrenal Insufficiency: A Prospective Study

OBJECTIVE Adrenal crisis (AC) is a life-threatening complication of adrenal insufficiency (AI), which according to retrospective data represents a significant clinical complication. Here we aimed to prospectively assess incidence of AC and mortality associated with AC in patients with chronic AI. METHODS A total of 423 patients with AI (primary AI, n = 221; secondary AI, n = 202) were prospectively followed up for 2 years. Baseline assessment included a general questionnaire and detailed written instructions on glucocorticoid dose adaptation during stress. Patients received follow-up questionnaires every 6 months and were contacted by phone in case of reported adrenal crisis. RESULTS A total of 423 data sets were available for baseline analysis, and 364 patients (86%) completed the whole study. Sixy-four AC in 767.5 patient-years were documented (8.3 crises per 100 patient-years). Precipitating causes were mainly gastrointestinal infection, fever, and emotional stress (20%, respectively) but also other stressful events (eg, major pain, surgery, strenuous physical activity, heat, pregnancy) or unexplained sudden onset of AC (7%) were documented. Patients with a previous AC were at higher risk of crisis (odds ratio 2.85, 95% confidence interval 1.5-5.5, P < .01). However, no further risk factors could be identified. Ten patients died during follow-up; in four cases death was associated with AC (0.5 AC related deaths per 100 patient-years). CONCLUSION Even in educated patients with chronic adrenal insufficiency, AC occurs in a substantial proportion of cases. Furthermore, we identified AC-associated mortality in approximately 6% of AC. Our findings further emphasize the need for improved management of AC in patients with chronic AI.

Observational Study Mortality in Treated Primary Aldosteronism The German Conn's Registry

In comparison with essential hypertension, primary aldosteronism (PA) is associated with an increased risk of cardiovascular morbidity. To date, no data on mortality have been published. We assessed mortality of patients treated for PA within the German Conns registry and identified risk factors for adverse outcome in a case-control study. Patients with confirmed PA treated in 3 university centers in Germany since 1994 were included in the analysis. All of the patients were contacted in 2009 and 2010 to verify life status. Subjects from the population-based F3 survey of the Cooperative Health Research in the Region of Augsburg served as controls. Final analyses were based on 600 normotensive controls, 600 hypertensive controls, and 300 patients with PA. Kaplan-Meyer survival curves were calculated for both cohorts. Ten-year overall survival was 95% in normotensive controls, 90% in hypertensive controls, and 90% in patients with PA (P value not significant). In multivariate analysis, age (hazard ratio, 1.09 per year [95% CI, 1.03–1.14]), angina pectoris (hazard ratio, 3.6 [95% CI, 1.04–12.04]), and diabetes mellitus (hazard ratio, 2.55 [95% CI, 1.07–6.09]) were associated with an increase in all-cause mortality, whereas hypokalemia (hazard ratio, 0.41 per mmol/L [95% CI, 0.17–0.99]) was associated with reduced mortality. Cardiovascular mortality was the main cause of death in PA (50% versus 34% in hypertensive controls; P<0.05). These data indicate that cardiovascular mortality is increased in patients treated for PA, whereas all-cause mortality is not different from matched hypertensive controls.

Effectiveness of eplerenone or spironolactone treatment in preserving renal function in primary aldosteronism.

OBJECTIVE Primary aldosteronism (PA) has deleterious effects on kidney function independent of blood pressure levels. Up to now, data on effectiveness of different PA therapies regarding renal function are scarce. DESIGN AND METHODS This prospective multi-center study included 29 patients with newly diagnosed PA evaluated before and 1 year after treatment initiation, and a second cohort including 119 patients who were evaluated 5.3 and 6.8 years after treatment initiation. Glomerular filtration rate (GFR), spot urine albumin excretion/urinary creatinine (UAE/Ucrea) ratio, biochemical parameters, and 24-h blood pressure were measured. In a larger cross-sectional cohort, renal function was evaluated depending on the type of treatment (adrenalectomy (ADX; n=86); spironolactone (n=65); and eplerenone (n=18)). RESULTS GFR and UAE/Ucrea ratio significantly decreased in newly diagnosed PA patients after treatment initiation. In the second cohort, GFR and UAE/Ucrea ratio did not change during study period, and blood pressure was well controlled. In the larger cross-sectional cohort, no differences were seen in GFR and UAE/Ucrea ratio between PA patients on different treatment regimens. However, eplerenone treatment showed lower potassium levels and higher number of required antihypertensive medications. CONCLUSIONS Renal dysfunction with elevated albuminuria was seen in PA patients and was reversible after treatment initiation. Medical therapies with spironolactone or eplerenone seem to be as effective as ADX regarding renal function and blood pressure; however, sufficient daily doses need to be given.

Steroid metabolome analysis reveals prevalent glucocorticoid excess in primary aldosteronism

BACKGROUND. Adrenal aldosterone excess is the most common cause of secondary hypertension and is associated with increased cardiovascular morbidity. However, adverse metabolic risk in primary aldosteronism extends beyond hypertension, with increased rates of insulin resistance, type 2 diabetes, and osteoporosis, which cannot be easily explained by aldosterone excess. METHODS. We performed mass spectrometry–based analysis of a 24-hour urine steroid metabolome in 174 newly diagnosed patients with primary aldosteronism (103 unilateral adenomas, 71 bilateral adrenal hyperplasias) in comparison to 162 healthy controls, 56 patients with endocrine inactive adrenal adenoma, 104 patients with mild subclinical, and 47 with clinically overt adrenal cortisol excess. We also analyzed the expression of cortisol-producing CYP11B1 and aldosterone-producing CYP11B2 enzymes in adenoma tissue from 57 patients with aldosterone-producing adenoma, employing immunohistochemistry with digital image analysis. RESULTS. Primary aldosteronism patients had significantly increased cortisol and total glucocorticoid metabolite excretion (all P < 0.001), only exceeded by glucocorticoid output in patients with clinically overt adrenal Cushing syndrome. Several surrogate parameters of metabolic risk correlated significantly with glucocorticoid but not mineralocorticoid output. Intratumoral CYP11B1 expression was significantly associated with the corresponding in vivo glucocorticoid excretion. Unilateral adrenalectomy resolved both mineralocorticoid and glucocorticoid excess. Postoperative evidence of adrenal insufficiency was found in 13 (29%) of 45 consecutively tested patients. CONCLUSION. Our data indicate that glucocorticoid cosecretion is frequently found in primary aldosteronism and contributes to associated metabolic risk. Mineralocorticoid receptor antagonist therapy alone may not be sufficient to counteract adverse metabolic risk in medically treated patients with primary aldosteronism. FUNDING. Medical Research Council UK, Wellcome Trust, European Commission.

Functional characterization of adrenal lesions using [123I]IMTO-SPECT/CT.

CONTEXT Adrenal tumors are highly prevalent and represent a wide range of different pathological entities. Conventional imaging often provides only limited information on the origin of these lesions. Novel specific imaging methods are, therefore, of great clinical interest. OBJECTIVE We evaluated [(123)I]iodometomidate ([(123)I]IMTO) imaging for noninvasive characterization of adrenal masses. DESIGN/SETTING This was a prospective monocentric diagnostic study in a tertiary care center. PATIENTS AND INTERVENTION A total of 51 patients with an adrenal lesion underwent [(123)I]IMTO imaging after injection of 185 MBq of [(123)I]IMTO. Sequential planar whole-body scans until 24 hours postinjection and single photon emission computed tomography (SPECT)/computed tomography imaging 4 to 6 hours postinjection were performed. MAIN OUTCOME MEASURE Sensitivity and specificity of [(123)I]IMTO imaging for the noninvasive characterization of adrenal lesions were measured. RESULTS Adrenocortical tissue showed high and specific tracer uptake with a short investigation time and low radiation exposure. Qualitative analysis of SPECT/computed tomography data resulted in a sensitivity of 89% and a specificity of 85% for differentiating adrenocortical tumors from lesions of nonadrenocortical origin. Receiver-operating characteristic analysis of semiquantitative data revealed a sensitivity of 83% and a specificity of 86% for identification of adrenocortical lesions at a cutoff value of tumor to liver ratio of 1.3. CONCLUSIONS [(123)I]IMTO is a highly specific radiotracer for imaging of adrenocortical tissue with a short investigation time and low radiation exposure. Because of the general availability of SPECT technology, [(123)I]IMTO scintigraphy has the potential to become a widely used tool to noninvasively characterize the biology of adrenal lesions.

Increased prevalence of diabetes mellitus and the metabolic syndrome in patients with primary aldosteronism of the German Conn's Registry

DESIGN Abnormalities in glucose homeostasis have been described in patients with primary aldosteronism (PA) but most studies show inconsistent results. Therefore, we aimed to compare the prevalence of type 2 diabetes mellitus and metabolic syndrome (MetS) in newly diagnosed PA patients to a matched control cohort of the background population. METHODS In total, 305 PA patients of the prospective German Conns Registry were compared to the population-based Study of Health In Pomerania (SHIP1; n=2454). A 1:1 match regarding sex, age, and BMI resulted in 269 matched pairs regarding type 2 diabetes and 183 matched pairs regarding MetS. Of the total, 153 PA patients underwent oral glucose tolerance testing (OGTT) at diagnosis and 38 PA patients were reevaluated at follow-up. RESULTS Type 2 diabetes and MetS were significantly more frequent in PA patients than in the control population (17.2% vs 10.4%, P=0.03; 56.8% vs 44.8%, P=0.02 respectively). Also, HbA1c levels were higher in PA patients than in controls (P<0.01). Of the total, 35.3% of non-diabetic PA patients showed an abnormal OGTT (¼ newly diagnosed type 2 diabetes and ¾ impaired glucose tolerance). PA patients with an abnormal OGTT at baseline presented with significantly improved 2 h OGTT glucose (P=0.01) at follow-up. We detected a negative correlation between 2 h OGTT glucose levels and serum potassium (P<0.01). CONCLUSIONS Type 2 diabetes and MetS are more prevalent in patients with PA than in controls matched for sex, age, BMI, and blood pressure. This may explain in part the increased cardiovascular disease morbidity and mortality in PA patients.

Clinical Management and Outcomes of Adrenal Hemorrhage Following Adrenal Vein Sampling in Primary Aldosteronism

Aldosterone-producing adenoma and bilateral adrenal hyperplasia account for >90% of all primary aldosteronism cases. Distinguishing between bilateral and unilateral disease is of fundamental importance because it allows targeted therapy. Adrenal vein sampling (AVS) is the only reliable means to preoperatively differentiate between unilateral and bilateral subtypes. A rare but serious complication of AVS is an adrenal hemorrhage (AH). We retrospectively examined in detail 24 cases of AH during AVS in 6 different referral hypertension centers. AH more often affected the right adrenal (n=18) than the left (n=5, P<0.001); 1 bilateral. Median duration of experience of the radiologist in AVS at the time of AH was 5.0 years (0.6–7.8) and AH occurred with both highly experienced (>10 years) and less experienced radiologists. Of 9 patients who suffered AH in the gland contralateral to an aldosterone-producing adenoma and who underwent complete (n=6) or partial (n=3) unilateral adrenalectomy, only one required long-term corticosteroid replacement for adrenal insufficiency. No reduction in blood pressure or biochemical resolution of primary aldosteronism occurred in any of those patients who experienced AH in the gland ipsilateral to an aldosterone-producing adenoma (n=6) or who had bilateral adrenal hyperplasia (n=9). No patient required invasive treatments to control bleeding or blood transfusion. In conclusion, AH usually has a positive outcome causing either no or minor effects on adrenal function, and AVS should remain the best approach to primary aldosteronism subtype differentiation.