The prevalence of familial hyperaldosteronism in apparently sporadic primary aldosteronism in Germany: a single center experience.

Primary aldosteronism (PA) is the most frequent cause of secondary arterial hypertension. To date 3 forms of familial hyperaldosteronism (FH) have been described accounting for a small percentage of all PA cases. In Germany, the prevalence of FH is currently unknown. Our aim was to determine the prevalence of familiarity in a large cohort of patients with PA. A total of 166 patients with apparently sporadic PA in Munich were investigated. FH types I, II, and III were identified using established clinical, biochemical, and molecular criteria. Among the 166 patients with PA, 2 patients (1.2%) reported a family history suggestive of FH. None of the 166 patients showed clinical, endocrine, or genetic evidence of FH type I. The 2 families had characteristic features of FH type II. Family A had 3 subjects affected out of 11 evaluated family members. Family B had 3 out of 4. Bilateral adrenal hyperplasia and unilateral adrenal adenoma were found within the same family. FH type I and FH type III are rare in Germany. With a prevalence of 1.2%, FH type II seems to be more common in apparently sporadic PA than had been assumed so far.

Saliva as a medium for aldosterone measurement in repeated sampling studies.

BACKGROUND: Saliva is a readily available biological fluid, making it convenient in diagnosis of diseases and in multi-sampling protocols. Several salivary steroids give a useful index of free plasma levels. Increased incidence of primary aldosteronism (PA) in approximately 10% of the hypertensive population has increased interest in the mineralocorticoid aldosterone. METHODS: A biotinylated-aldosterone tracer and a commercially available antibody are used in a time-resolved fluorescence immunoassay (TR-FIA) to measure salivary aldosterone (SA). Saliva was collected in various multi-sampling protocols: Investigation of diurnal rhythm in healthy and PA patients, ACTH stimulation test and posture test in healthy subjects. RESULTS: Method validation showed a sensitivity of 19 ng/L and intra-/inter-assay precision between 7.2-10.1% and 8.7-15.7%, respectively. SA correlated significantly (y = 0.2995x +/- 0.01, r(2)=0.60) to plasma aldosterone measured by a commercial radioimmunoassay. SA (median; 95%CI) was at 111 (95-127)ng/L in PA (n=84) and 50 (44-56)ng/L in healthy subjects (n=60). After change in posture, aldosterone increased in both, saliva (57 (47-63)ng/L to 95 (84-117)ng/L) and plasma (26 (26-41)ng/L to 135 (110-181)ng/L). Peak levels were reached after 1h, and were higher in females than in males. CONCLUSIONS: SA correlates well to plasma aldosterone and mirrors responses during conditions of stress. SA is significantly higher in PA, and the diurnal rhythm seen in the healthy is blunted in PA. We additionally found gender-dependent differential responses to posture, with higher increases in females. Measurement of aldosterone in saliva presents a useful and convenient method for application in multi-sampling studies.

Screening for membrane hormone receptor expression in primary aldosteronism.

OBJECTIVE: The investigation of expression and functional relevance of G-protein coupled receptors in primary aldosteronism (PA) by molecular and clinical studies. PATIENTS AND METHODS: Tissues of 14 aldosterone-producing adenomas (APA), of one unilateral adrenal hyperplasia and of six healthy adult adrenal glands; 12 patients with confirmed PA due to APA; (n=5), idiopathic hyperaldosteronism (n=7) and 8 control subjects (C). The tissues were subjected to a quantitative PCR for determination of mRNA expression levels of AT2R1, GIPR, MC2R, GnRHR, LHR, TRHR, TSHR, glucagon-R, V1aR, V2R, and 5-HT4R. The patients and controls were enrolled in a test protocol consisting of stimulation by posture, mixed meal, ACTH, GnRH, TRH, glucagon, vasopressin, and metoclopramide (MCP). Three patients could be analyzed by both studies. A positive response was defined as an aldosterone increase of more than 50% following stimulation. RESULTS: All the tissues revealed AT2R1, MC2R, AVPR, and 5-HT4R mRNA expression. LHR mRNA was found in normal adrenals and 13 adrenal tumors. By contrast with normal adrenals tumorous adrenal tissue expressed GnRHR mRNA (4/15) and TSHR mRNA (1/15). Both the patients and controls responded to posture, ACTH, glucagon, AVP, and MCP. Specific responses were seen in one patient following TRH and three patients following GnRH stimulation. CONCLUSIONS: We provide evidence for peptide hormone responsiveness to various peptide hormones in patients with PA, including GnRH and TRH. A good correlation between clinical and molecular testing could be observed, making an involvement of the receptor expressed in PA possible.

Regulation of human MC2-R gene expression by CREB, CREM, and ICER in the adrenocortical cell line Y1.

The MC2-Receptor (melanocortin 2 receptor, MC2-R) is a Gs-protein coupled receptor that is upregulated by its own ligand ACTH and by forskolin. The mechanisms regulating MC2-R expression are still unclear. We therefore investigated the role of the stimulatory transcription factors CREB and CREM and the inhibitory factor ICER for regulation of human MC2-R expression. We cotransfected mouse adrenocortical Y1 cells with luciferase reporter gene vectors containing full length and deleted human MC2-R promoter constructs with expression plasmids for CREB, CREBS133A, CREMtau, CREMtauS117A, or ICER. Direct protein-DNA interaction was investigated by EMSA. Wild type CREB did not significantly affect promoter activity due to high endogenous CREB activity. However, CREBS133A decreased forskolin stimulated MC2-R promoter activity by 48+/-5% (mean+/-SEM) while unstimulated values remained unchanged. CREMtau moderately increased basal and forskolin stimulated luciferase activity in a dose-dependent manner (maximum effect 252+/-24% and 186+/-13% VS. control vector, respectively). While this effect required the full length promoter, cAMP stimulation was retained in shorter constructs. ICER reduced basal luciferase activity in Y1 cells by 17+/-28%, but completely abolished forskolin stimulation. Although 5'-deletion constructs mapped the minimum promoter region required for ICER effect to the shortest -64/+40 construct, direct protein DNA interaction in this promoter region could not be identified by EMSA. Moreover, mutation of the SF-1 binding sites, which retained ICER dependent inhibition, excluded SF-1 to be required for this effect. We conclude from these data that transcription factors of the CREB/CREM/ATF family have a moderate effect on human MC2-R promoter activity, but seem to play a minor role in transmitting stimulation of the cAMP pathway to increased MC2-R expression.

The role of the ACTH receptor in adrenal tumors: identification of a novel microsatellite marker.

In vitro, the growth inhibiting effect of ACTH on adrenocortical cells is well documented, even though there are reports of opposite effects under defined cell culture conditions. In vivo, activation of the ACTH receptor (ACTHR) has a trophic effect on the adrenal cortex, while the effects on proliferation are still under discussion, especially since other POMC derived peptides have been characterized. However, ACTH is thought to act as a differentiation factor with inhibiting effects on tumor growth. In undifferentiated adrenocortical carcinomas, ACTHR expression is frequently lost, which is associated with extensive tumor growth. We describe a new microsatellite marker within the intron of the ACTHR gene termed ACTHRint1. In a series of 114 patients with various adrenal and non-adrenal tumors, the rate of heterozygosity was 100 %. Only one out of 57 patients with adrenocortical adenoma showed LOH at the ACTHR locus, whereas 4 of 10 carcinomas had loss of one allele. Patients suffering from tumors with LOH showed a more aggressive disease course and had earlier recurrences with poor prognosis. These data confirm earlier findings that adrenocortical carcinomas frequently show loss of ACTHR expression, which is associated with a more aggressive tumor growth. However, whether the ACTHR is directly involved in tumor growth or acts a marker of differentiation that is lost in more advanced tumor stages is still not clear.

[Hypoglycemia and transient diabetes mellitus in an insulin autoimmune syndrome]. / Hypoglykämien und transienter Diabetes mellitus bei einem Autoimmun-Insulinsyndrom.

HISTORY AND CLINICAL FINDINGS: A 53-year-old Caucasian woman presented with repeated episodes of hypoglycemia. Self-monitored blood glucose levels during the attacks were between 40 and 60 mg/dl (2.2-3.3 mmol/l). INVESTIGATIONS: An oral glucose tolerance test performed over 210 minutes showed normal baseline glucose levels, markedly elevated levels of serum insulin and slightly elevated C-peptide concentrations. During the test, a marked increase of insulin and a normal increment of C-peptide were observed. The tentative diagnosis of an insulinoma was raised and a 72 h fasting test performed, throughout which the insulin-glucose-ratio was pathologically elevated, whereas C-peptide levels were only slightly elevated. DIAGNOSIS: Strongly positive levels of insulin antibodies led to the diagnosis of an insulin autoimmune syndrome. TREATMENT AND COURSE: This syndrome is caused by IgG-insulin-complexes with prolonged plasma half-life in the presence of reduced insulin action. The therapy consisted of fractionated meals to avoid hyperinsulinism and following hypoglycemic episodes. After four months a spontaneous clinical remission was observed. CONCLUSION: The autoimmune insulin syndrome is a rare cause of recurrent, spontaneous hypoglycemia in Europe in non diabetic patients. Its prognosis is good as there is a high rate of spontaneous clinical remission in up to 80 % of patients.

[Acute upper gastrointestinal bleeding as initial manifestation of a gastrointestinal stromal tumor]. / Akute obere gastrointestinale Blutung als Erstmanifestation eines gastrointestinalen Stromatumors.

HISTORY: An 80-years-old man was admitted to our clinic because of upper gastrointestinal bleeding with tarry stool for 3 days after taking non steroidal antiinflammatory drugs (NSAID) for back pain. The history was otherwise unremarkable. INVESTIGATIONS: Laboratory results showed anaemia. Initial endoscopy revealed acute bleeding from an elevated ulcer in the pars inferior of the duodenum. The bleeding was successfully treated by epinephrine and fibrin injection. Biopsies showed inflammatory changes without presence of malignant cells. In the CT scan of the abdomen there was a mass near the ligament of Treitz of 6.3 cm in diameter adjacent to the duodenum. CLINICAL COURSE: The abdominal tumor was not suitable for ultrasound-guided biopsy. Therefore, laparotomy and surgical resection of the tumor were performed. Histology showed a gastrointestinal stromal tumor (GIST) with infiltration of the muscle layer of the duodenal wall with one small local metastasis. No lymph node metastases were present. The tumor was surgically completely removed and the regular follow-up examinations have fo far shown no evidence for tumor recurrence or metastases. CONCLUSIONS: In upper gastrointestinal bleeding from unusual sites, GIST has to be considered as an underlying disease even if endoscopic biopsies are negative for neoplastic changes.

Abnormal pentagastrin response in a patient with pseudohypoparathyroidism.

The case of a 25 year old female patient with pseudohypoparathyroidism type I (PHP) and hypercalcitoninaemia is reported. She was referred to our clinic because of recurrent hypocalcaemia associated with paraesthesias and muscle cramps. She had no signs of Albright hereditary osteodystrophy (AHO), a normal mental status and no family history of hypocalcaemia or any other endocrine disease. Considering the laboratory results with hypocalcaemia, hyperphosphataemia, normal vitamin D and normal creatinine with an extraordinary elevated PTH we diagnosed pseudohypoparathyroidism type I. She had delayed pubertal development with menarche in the age of 20 and hypothyroidism with an atrophic thyroid since she was 22 years old. Calcitonin (CT) was increased and the performed pentagastrin test showed an excessive CT-response with a peak of 725 pg/ml after 2 min. Up to now there are only three reports of patients with PHP and hypercalcitoninaemia. An abnormal pentagastrin response is known to be a specific marker for medullary thyroid carcinoma, but there were no signs of any malignant disease, even after one year of follow-up. The most reasonable cause for the pathological pentagastrin response might be chronic hypocalcaemia. When interpreting a pathological pentagastrin test in a patient with PHP the specifity of the test might be diminished and a careful observational strategy might be appropriate.

Discerning malignancy in adrenocortical tumors: are molecular markers useful?

OBJECTIVE: Adrenocortical carcinoma (ACC) is a rare neoplasm with poor prognosis. Discerning ACCs from benign adenomas histologically may be difficult if invasion into surrounding tissues or metastases are missing. DESIGN: In order to establish molecular markers for malignancy, we analyzed seven normal adrenals, three massive macronodular ACTH-independent adrenocortical hyperplasias (MMAHs), 30 adrenocortical adenomas (ACAs) and ten ACCs. METHODS: All tissues were studied for the presence of alterations in the p53 tumor suppressor gene using the PAb 1801 antibody, which detects mutant p53 protein and the pYNZ22 microsatellite marker to show loss of heterozygosity (LOH) at 17p, for expression of the proliferation-associated antigen Ki67 using the MIB1 antibody, for the rate of apoptotic tumor cells with the TdT-mediated dUTP biotin nick end labeling (TUNEL) method, and for LOH of 11q13 (menin gene locus) with the D11S956 microsatellite marker. RESULTS: 0/3 MMAH, 1/28 ACA and 3/10 ACC revealed immunopositive staining for p53. LOH for pYNZ22 was observed in 1/3 MMAH, 1/23 informative ACA and 6/6 informative ACC. The rate of apoptotic cells was significantly higher in ACC (P<0.0001 by ANOVA) than in ACA but there was some overlap between groups. The Ki67 index (% immunopositive cells) was 1.9+/-1.30% (mean+/-s.d.) in normal adrenals, 3.47+/-1.37% in MMAH, and 2.11+/-1.01% in ACA. ACC had the highest Ki67 index of 11.94+/-7.58% distinguishing all ACC from the ACA and MMAH studied with a cut-off level of 5%. LOH for 11q13 was detected in 2/3 MMAH, 5/26 ACA and 6/8 ACC. CONCLUSIONS: We conclude that a Ki67 index above 5% is a sensitive and specific indicator of ACC and may be useful in the differentiation of adenomas from carcinomas.

Multiple endocrine neoplasia type 1 gene expression is normal in sporadic adrenocortical tumors.

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder with neoplasia of the anterior pituitary, the parathyroid, the endocrine pancreas and other endocrine tissues including the adrenal cortex. The tumor-suppressor gene causing this disease was identified at the gene locus 11q13. We recently reported that adrenocortical carcinomas frequently show loss of heterozygosity (LOH) of 11q13, but do not contain point mutations within the MEN1-coding region. To investigate whether reduced gene expression (for example by mutations within the MEN1 promoter) may contribute to the tumorigenesis of sporadic adrenocortical tumors, 24 adrenocortical specimen were studied by Northern blot analysis. This series included six adrenocortical carcinomas, four cortisol-producing adenomas, six aldosterone-producing adenomas, three endocrine-inactive adenomas and six normal adrenal glands. The presence of LOH of 11q13 was investigated using five polymorphic microsatellite markers (D11S956, PYGM, D11S4939, D11S4946 and D11S987) close to the MEN1 gene. Poly-A mRNA was hybridized with a PCR-generated cDNA probe of the MEN1 gene, a cDNA of the former MEN1 candidate gene phospholipase (PLC) beta3 and a mouse beta-actin cDNA for normalization. LOH of 11q13 was detected in five out of six carcinomas and two inactive adenomas, but in none of the hormone-producing adenomas. Compared with normal adrenals (100+/-6. 5%, mean+/-s.e.m.) MEN1 mRNA in adrenocortical tumors was expressed in similar amounts (carcinomas 109+/-11%, cortisol-producing adenomas 131+/-10%, aldosterone-producing adenomas 113+/-13%, endocrine-inactive adenomas 111+/-2%) with the exception of one adrenocortical carcinoma with low MEN1 mRNA expression (66%). PLCbeta3 mRNA expression showed a variable pattern without reaching significant differences between the groups. We conclude that since mRNA levels were unaltered in the majority of tumors, mutations of the MEN1 gene causing altered gene transcription is unlikely to be a major pathogenic factor of sporadic adrenocortical tumors.