Assessing Lateralization Index of Adrenal Venous Sampling for Surgical Indication in Primary Aldosteronism.

BACKGROUND: Clinical practice guidelines recommend the Lateralization Index (LI) as the standard for determining surgical eligibility in primary aldosteronism (PA). Our goal was to identify the optimal LI cut-offs in adrenal venous sampling (AVS) for diagnosing PA that is amenable to surgical cure. METHODS: We conducted a retrospective international cohort study across 16 institutions in 11 countries, including 1,550 patients with PA who underwent AVS, with and/or without ACTH stimulation. The establishment of optimal cut-offs was informed by a survey of 82 PA patients in Japan, aimed at determining the LI cut-off aligned with patient expectations for a surgical cure rate. RESULTS: The survey revealed that a median cure rate expectation of 80% would motivate PA patients towards undergoing adrenalectomy. The optimal LI cut-offs achieving an adjusted positive predictive value (PPV) of 80% were identified as 3.8 for unstimulated AVS and 3.4 for ACTH-stimulated AVS. Furthermore, a contralateral ratio of less than 0.4 and the detection of an adrenal nodule on CT imaging were identified as independent predictors of surgically curable PA. Incorporating these factors with the optimal LI cut-offs, the adjusted PPV increased to 96.6% for unstimulated AVS and 89.6% for ACTH-stimulated AVS. No clear differences in predictive ability between unstimulated and ACTH-stimulated LI were found. CONCLUSIONS AND RELEVANCE: The present study clarified the optimal LI cut-offs for without and with ACTH stimulation. The presence of contralateral suppression and adrenal nodule on CT imaging seems to provide additional available information besides LI for surgical indication.

When rare diseases crisscross within the same patient: von Hippel-Lindau and type 1 gastric neuroendocrine tumor.

Von-Hippel-Lindau (VHL) is a genetic multisystem disorder characterized by visceral cysts and benign and malignant tumors in various organs. Herein, we present the case of a 23-year-old woman with VHL presenting with multiple gastric neuroendocrine neoplasms (gNENs) type 1 in the context of chronic autoimmune gastritis (CAG). Although gNENs are not acknowledged as a typical entity in VHL patients, in the present case, gNENs were composed of neoplastic cells with clear cytoplasm usually seen in tumors related to VHL disease. We additionally performed a literature review on the presence of neuroendocrine clear cell tumors and report on further cases of clear cell NENs. The present case illustrates that clear-cell transformation in gNENs may be due to the dual genetic background of the patient; the real oncogenic stimulus may be more closely related to CAG than to VHL disease accompanied by an interplay between neoplastic and autoimmune processes. Therefore, close monitoring of patients with clear cell NENs appears to be important before excluding VHL disease, even in the context of phenotypically unrelated diseases.

Surgical Treatment of Solitary Metachronous Adrenal Metastasis from Urothelial Carcinoma of the Urinary Bladder.

Urothelial cancer is a common neoplasm and metastatic disease correlates with a poor prognosis. Isolated adrenal gland metastases of urothelial carcinoma are quite rare, and management options can decide a patient's prognosis. Herein we report the case of a 76-year-old man with a metachronous solitary adrenal metastasis from a bladder carcinoma, who underwent adrenalectomy as part of his treatment. Furthermore, we discuss the cases of solitary adrenal metastases of urothelial carcinoma available in the literature, to identify key features to direct appropriate treatment of this rare metastatic site of urothelial cancer and improve prognosis and survival. Still, further prospective studies are needed to design effective therapeutic strategies.

The Role of Somatostatin Analogues in the Control of Diarrhea and Flushing as Markers of Carcinoid Syndrome: A Systematic Review and Meta-Analysis.

BACKGROUND: Somatostatin analogues (SSAs) are the cornerstone of treatment for carcinoid syndrome (CS)-related symptoms. The aim of this systematic review and meta-analysis is to evaluate the percentage of patients achieving partial (PR) or complete response (CR) with the use of long-acting SSAs in patients with CS. METHODS: A systematic electronic literature search was conducted in PubMed, Cochrane, and Scopus to identify eligible studies. Any clinical trials reporting data on the efficacy of SSAs to alleviate symptoms in adult patients were considered as potentially eligible. RESULTS: A total of 17 studies reported extractable outcomes (PR/CR) for quantitative synthesis. The pooled percentage of patients with PR/CR for diarrhea was estimated to be 0.67 (95% confidence interval (CI): 0.52-0.79, I2 = 83%). Subgroup analyses of specific drugs provided no evidence of a differential response. With regards to flushing, the pooled percentage of patients with PR/CR was estimated to be 0.68 (95% CI: 0.52-0.81, I2 = 86%). Similarly, no evidence of a significant differential response in flushing control was documented. CONCLUSIONS: We estimate there is a 67-68% overall reduction in symptoms of CS associated with SSA treatment. However, significant heterogeneity was detected, possibly revealing differences in the disease course, in management and in outcome definition.

Deoxyguanosine kinase mutation F180S is associated with a lean phenotype in mice.

BACKGROUND: Deoxyguanosine kinase (DGUOK) deficiency is one of the genetic causes of mitochondrial DNA depletion syndrome (MDDS) in humans, leading to the hepatocerebral or the isolated hepatic form of MDDS. Mouse models are helpful tools for the improvement of understanding of the pathophysiology of diseases and offer the opportunity to examine new therapeutic options. METHODS: Herein, we describe the generation and metabolic characterization of a mouse line carrying a homozygous DguokF180S/F180S mutation derived from an N-ethyl-N-nitrosourea-mutagenesis screen. Energy expenditure (EE), oxygen consumption (VO2) and carbon dioxide production (VCO2) were assessed in metabolic cages. LC-MS/MS was used to quantify plasma adrenal steroids. Plasma insulin and leptin levels were quantified with commercially available assay kits. RESULTS: Mutant animals displayed significantly lower body weights and reduced inguinal fat pad mass, in comparison to unaffected littermates. Biochemically, they were characterized by significantly lower blood glucose levels, accompanied by significantly lower insulin, total cholesterol, high density lipoprotein and triglyceride levels. They also displayed an almost 2-fold increase in transaminases. Moreover, absolute EE was comparable in mutant and control mice, but EE in mutants was uncoupled from their body weights. Histological examination of inguinal white adipose tissue (WAT) revealed adipocytes with multilocular fat droplets reminiscent of WAT browning. In addition, mRNA and protein expression of Ucp1 was increased. Mutant mice also presented differing mitochondrial DNA content in various tissues and altered metabolic activity in mitochondria, but no further phenotypical or behavioral abnormalities. Preliminary data imply normal survival of DguokF180S/F180S mutant animals. CONCLUSION: Taken together, DGUOK mutation F180S leads to a lean phenotype, with lower glucose, insulin, and lipid levels rendering this mouse model not only useful for the study of MDDS forms but also for deciphering mechanisms resulting in a lean phenotype.

The metabolic phenotype of patients with primary aldosteronism: impact of subtype and sex - a multicenter-study of 3566 Caucasian and Asian subjects.

Background: Accumulating evidence suggests that primary aldosteronism (PA) is associated with several features of the metabolic syndrome, in particular with obesity, type 2 diabetes mellitus, and dyslipidemia. Whether these manifestations are primarily linked to aldosterone-producing adenoma (APA) or bilateral idiopathic hyperaldosteronism (IHA) remains unclear. The aim of the present study was to investigate differences in metabolic parameters between APA and IHA patients and to assess the impact of treatment on these clinical characteristics. Methods: We conducted a retrospective multicenter study including 3566 patients with APA or IHA of Caucasian and Asian origin. We compared the prevalence of metabolic disorders between APA and IHA patients at the time of diagnosis and 1-year post-intervention, with special references to sex differences. Furthermore, correlations between metabolic parameters and plasma aldosterone, renin, or plasma cortisol levels after 1 mg dexamethasone (DST) were performed. Results: As expected, APA patients were characterized by higher plasma aldosterone and lower serum potassium levels. Only female IHA patients demonstrated significantly worse metabolic parameters than age-matched female APA patients, which were associated with lower cortisol levels upon DST. One-year post-intervention, female adrenalectomized patients showed deterioration of their lipid profile, when compared to patients treated with mineralocorticoid receptor antagonists. Plasma aldosterone levels negatively correlated with the BMI only in APA patients. Conclusions: Metabolic alterations appear more prominent in women with IHA. Although IHA patients have worse metabolic profiles, a correlation with cortisol autonomy is documented only in APAs, suggesting an uncoupling of cortisol action from metabolic traits in IHA patients.

Hobnail Papillary Thyroid Carcinoma, A Systematic Review and Meta-Analysis.

Although papillary thyroid carcinoma (PTC) is considered to have an excellent prognosis, some recently identified more aggressive variants show reduced overall survival rates. Hobnail PTC (HPTC) was newly recognized as one of these aggressive forms, affecting recurrence, metastasis, and overall survival rates. Herein, we performed a systematic review and meta-analysis of studies including cases or case series with patients with HPTC. Furthermore, we included our individual case series consisting of six patients. The pooled mortality rate in the cohort, consisting of 290 patients, was 3.57 (95% CI 1.67−7.65) per 100 person/years. No sex differences could be observed concerning mortality (p = 0.62), but older age and tumor size significantly affected mortality (p = 0.004 and p = 0.02, respectively). The percentage of hobnail cells did not affect mortality (p = 0.97), neither did the presence of BRAF mutations. Classical characteristics such as the presence of extrathyroidal extension (p = 0.001), distant metastases (p < 0.001), and lymph node metastases (p < 0.001) all had a significant impact on mortality. Thus, HPTC appears to correlate with worse overall survival, and all PTC cases should be carefully assessed for this variant.

Age-dependent and sex-dependent disparity in mortality in patients with adrenal incidentalomas and autonomous cortisol secretion: an international, retrospective, cohort study.

BACKGROUND: The association between cortisol secretion and mortality in patients with adrenal incidentalomas is controversial. We aimed to assess all-cause mortality, prevalence of comorbidities, and occurrence of cardiovascular events in uniformly stratified patients with adrenal incidentalomas and cortisol autonomy (defined as non-suppressible serum cortisol on dexamethasone suppression testing). METHODS: We conducted an international, retrospective, cohort study (NAPACA Outcome) at 30 centres in 16 countries. Eligible patients were aged 18 years or older with an adrenal incidentaloma (diameter ≥1 cm) detected between Jan 1, 1996, and Dec 31, 2015, and availability of a 1 mg dexamethasone suppression test result from the time of the initial diagnosis. Patients with clinically apparent hormone excess, active malignancy, or follow-up of less than 36 months were excluded. Patients were stratified according to the 0800-0900 h serum cortisol values after an overnight 1 mg dexamethasone suppression test; less than 50 nmol/L was classed as non-functioning adenoma, 50-138 nmol/L as possible autonomous cortisol secretion, and greater than 138 nmol/L as autonomous cortisol secretion. The primary endpoint was all-cause mortality. Secondary endpoints were the prevalence of cardiometabolic comorbidities, cardiovascular events, and cause-specific mortality. The primary and secondary endpoints were assessed in all study participants. FINDINGS: Of 4374 potentially eligible patients, 3656 (2089 [57·1%] with non-functioning adenoma, 1320 [36·1%] with possible autonomous cortisol secretion, and 247 [6·8%] with autonomous cortisol secretion) were included in the study cohort for mortality analysis (2350 [64·3%] women and 1306 [35·7%] men; median age 61 years [IQR 53-68]; median follow-up 7·0 years [IQR 4·7-10·2]). During follow-up, 352 (9·6%) patients died. All-cause mortality (adjusted for age, sex, comorbidities, and previous cardiovascular events) was significantly increased in patients with possible autonomous cortisol secretion (HR 1·52, 95% CI 1·19-1·94) and autonomous cortisol secretion (1·77, 1·20-2·62) compared with patients with non-functioning adenoma. In women younger than 65 years, autonomous cortisol secretion was associated with higher all-cause mortality than non-functioning adenoma (HR 4·39, 95% CI 1·93-9·96), although this was not observed in men. Cardiometabolic comorbidities were significantly less frequent with non-functioning adenoma than with possible autonomous cortisol secretion and autonomous cortisol secretion (hypertension occurred in 1186 [58·6%] of 2024 patients with non-functioning adenoma, 944 [74·0%] of 1275 with possible autonomous cortisol secretion, and 179 [75·2%] of 238 with autonomous cortisol secretion; dyslipidaemia occurred in 724 [36·2%] of 1999 patients, 547 [43·8%] of 1250, and 123 [51·9%] of 237; and any diabetes occurred in 365 [18·2%] of 2002, 288 [23·0%] of 1250, and 62 [26·7%] of 232; all p values <0·001). INTERPRETATION: Cortisol autonomy is associated with increased all-cause mortality, particularly in women younger than 65 years. However, until results from randomised interventional trials are available, a conservative therapeutic approach seems to be justified in most patients with adrenal incidentaloma. FUNDING: Deutsche Forschungsgemeinschaft, Associazione Italiana per la Ricerca sul Cancro, Università di Torino.

Transcriptomics, Epigenetics, and Metabolomics of Primary Aldosteronism.

INTRODUCTION: Primary aldosteronism (PA) is the most common cause of endocrine hypertension, mainly caused by aldosterone-producing adenomas or hyperplasia; understanding its pathophysiological background is important in order to provide ameliorative treatment strategies. Over the past several years, significant progress has been documented in this field, in particular in the clarification of the genetic and molecular mechanisms responsible for the pathogenesis of aldosterone-producing adenomas (APAs). METHODS: Systematic searches of the PubMed and Cochrane databases were performed for all human studies applying transcriptomic, epigenetic or metabolomic analyses to PA subjects. Studies involving serial analysis of gene expression and microarray, epigenetic studies with methylome analyses and micro-RNA expression profiles, and metabolomic studies focused on improving understanding of the regulation of autonomous aldosterone production in PA were all included. RESULTS: In this review we summarize the main findings in this area and analyze the interplay between primary aldosteronism and several signaling pathways with differential regulation of the RNA and protein expression of several factors involved in, among others, steroidogenesis, calcium signaling, and nuclear, membrane and G-coupled protein receptors. Distinct transcriptomic and metabolomic patterns are also presented herein, depending on the mutational status of APAs. In particular, two partially opposite transcriptional and steroidogenic profiles appear to distinguish APAs carrying a KCNJ5 mutation from all other APAs, which carry different mutations. CONCLUSIONS: These findings can substantially contribute to the development of personalized treatment in patients with PA.

Changing biological behaviour of NETs during the evolution of the disease: progress on progression.

Following improvements in the management and outcome of neuroendocrine neoplasms (NENs) in recent years, we see a subset, particularly of pancreatic NENs, which become more aggressive during the course of the disease. This is reflected by an increase in the Ki-67 labelling index, as a marker of proliferation, which may lead to an occasion of increase in grading, but generally does not appear to be correlated with histologically confirmed dedifferentiation. A systematic review of the literature was performed in PubMed, Cochrane Library, and Embase until May 2020 to identify cases that have behaved in such a manner. We screened 244 articles: only seven studies included cases in their cohort, or in a subset of the cohort studied, with a proven increase in the Ki-67 during follow-up through additional biopsy. In addition to these studies, we have also tried to identify possible pathophysiological mechanisms implicated in advanced NENs, although currently no studies appear to have addressed the mechanisms implicated in the switch to a more aggressive biological phenotype over the course of the disease. Such progression of the disease course may demand a change in the management. Summarising the overall evidence, we suggest that future studies should concentrate on changes in the molecular pathways during disease progression with sequential biopsies in order to shed light on the mechanisms that render a neoplasm more aggressive than its initial phenotype or genotype.

Urine steroid metabolomics for the differential diagnosis of adrenal incidentalomas in the EURINE-ACT study: a prospective test validation study.

BACKGROUND: Cross-sectional imaging regularly results in incidental discovery of adrenal tumours, requiring exclusion of adrenocortical carcinoma (ACC). However, differentiation is hampered by poor specificity of imaging characteristics. We aimed to validate a urine steroid metabolomics approach, using steroid profiling as the diagnostic basis for ACC. METHODS: We did a prospective multicentre study in adult participants (age ≥18 years) with newly diagnosed adrenal masses. We assessed the accuracy of diagnostic imaging strategies based on maximum tumour diameter (≥4 cm vs <4 cm), imaging characteristics (positive vs negative), and urine steroid metabolomics (low, medium, or high risk of ACC), separately and in combination, using a reference standard of histopathology and follow-up investigations. With respect to imaging characteristics, we also assessed the diagnostic utility of increasing the unenhanced CT tumour attenuation threshold from the recommended 10 Hounsfield units (HU) to 20 HU. FINDINGS: Of 2169 participants recruited between Jan 17, 2011, and July 15, 2016, we included 2017 from 14 specialist centres in 11 countries in the final analysis. 98 (4·9%) had histopathologically or clinically and biochemically confirmed ACC. Tumours with diameters of 4 cm or larger were identified in 488 participants (24·2%), including 96 of the 98 with ACC (positive predictive value [PPV] 19·7%, 95% CI 16·2-23·5). For imaging characteristics, increasing the unenhanced CT tumour attenuation threshold to 20 HU from the recommended 10 HU increased specificity for ACC (80·0% [95% CI 77·9-82·0] vs 64·0% [61·4-66.4]) while maintaining sensitivity (99·0% [94·4-100·0] vs 100·0% [96·3-100·0]; PPV 19·7%, 16·3-23·5). A urine steroid metabolomics result indicating high risk of ACC had a PPV of 34·6% (95% CI 28·6-41·0). When the three tests were combined, in the order of tumour diameter, positive imaging characteristics, and urine steroid metabolomics, 106 (5·3%) participants had the result maximum tumour diameter of 4 cm or larger, positive imaging characteristics (with the 20 HU cutoff), and urine steroid metabolomics indicating high risk of ACC, for which the PPV was 76·4% (95% CI 67·2-84·1). 70 (3·5%) were classified as being at moderate risk of ACC and 1841 (91·3%) at low risk (negative predictive value 99·7%, 99·4-100·0). INTERPRETATION: An unenhanced CT tumour attenuation cutoff of 20 HU should replace that of 10 HU for exclusion of ACC. A triple test strategy of tumour diameter, imaging characteristics, and urine steroid metabolomics improves detection of ACC, which could shorten time to surgery for patients with ACC and help to avoid unnecessary surgery in patients with benign tumours. FUNDING: European Commission, UK Medical Research Council, Wellcome Trust, and UK National Institute for Health Research, US National Institutes of Health, the Claire Khan Trust Fund at University Hospitals Birmingham Charities, and the Mayo Clinic Foundation for Medical Education and Research.

Clinical spectrum of primary adrenal lymphoma: results of a multicenter cohort study.

Purpose: We sought to refine the clinical picture of primary adrenal lymphoma (PAL), a rare lymphoid malignancy with predominant adrenal manifestation and risk of adrenal insufficiency. Methods: Ninety-seven patients from 14 centers in Europe, Canada and the United States were included in this retrospective analysis between 1994 and 2017. Results: Of the 81 patients with imaging data, 19 (23%) had isolated adrenal involvement (iPAL), while 62 (77%) had additional extra-adrenal involvement (PAL+). Among patients who had both CT and PET scans, 18FDG-PET revealed extra-adrenal involvement not detected by CT scan in 9/18 cases (50%). The most common clinical manifestations were B symptoms (55%), fatigue (45%), and abdominal pain (35%). Endocrinological assessment was often inadequate. With a median follow-up of 41.6 months, 3-year progression-free (PFS) and overall (OS) survival rates in the entire cohort were 35.5% and 39.4%, respectively. The hazard ratios of iPAL for PFS and OS were 40.1 (95% CI: 2.63-613.7, P = 0.008) and 2.69 (95% CI: 0.61-11.89, P = 0.191), respectively. PFS was much shorter in iPAL vs PAL+ (median 4 months vs not reached, P = 0.006), and OS also appeared to be shorter (median 16 months vs not reached), but the difference did not reach statistical significance (P = 0.16). Isolated PAL was more frequent in females (OR = 3.81; P = 0.01) and less frequently associated with B symptoms (OR = 0.159; P = 0.004). Conclusion: We found unexpected heterogeneity in the clinical spectrum of PAL. Further studies are needed to clarify whether clinical distinction between iPAL and PAL+ is corroborated by differences in molecular biology.

Impact of 123I-MIBG Scintigraphy on Clinical Decision-Making in Pheochromocytoma and Paraganglioma.

CONTEXT: Cross-sectional imaging with CT or MRI is regarded as a first-choice modality for tumor localization in patients with pheochromocytoma and paraganglioma (PPGL). 123I-labeled metaiodobenzylguanidine (123I-MIBG) is widely used for functional imaging but the added diagnostic value is controversial. OBJECTIVE: To establish the virtual impact of adding 123I-MIBG scintigraphy to CT or MRI on diagnosis and treatment of PPGL. DESIGN: International multicenter retrospective study. INTERVENTION: None. PATIENTS: Two hundred thirty-six unilateral adrenal, 18 bilateral adrenal, 48 unifocal extra-adrenal, 12 multifocal, and 26 metastatic PPGL. MAIN OUTCOME MEASURES: Patients underwent both anatomical imaging (CT and/or MRI) and 123I-MIBG scintigraphy. Local imaging reports were analyzed centrally by two independent observers who were blinded to the diagnosis. Imaging-based diagnoses determined by CT/MRI only, 123I-MIBG only, and CT/MRI combined with 123I-MIBG scintigraphy were compared with the correct diagnoses. RESULTS: The rates of correct imaging-based diagnoses determined by CT/MRI only versus CT/MRI plus 123I-MIBG scintigraphy were similar: 89.4 versus 88.8%, respectively (P = 0.50). Adding 123I-MIBG scintigraphy to CT/MRI resulted in a correct change in the imaging-based diagnosis and ensuing virtual treatment in four cases (1.2%: two metastatic instead of nonmetastatic, one multifocal instead of single, one unilateral instead of bilateral adrenal) at the cost of an incorrect change in seven cases (2.1%: four metastatic instead of nonmetastatic, two multifocal instead of unifocal and one bilateral instead of unilateral adrenal). CONCLUSIONS: For the initial localization of PPGL, the addition of 123I-MIBG scintigraphy to CT/MRI rarely improves the diagnostic accuracy at the cost of incorrect interpretation in others, even when 123I-MIBG scintigraphy is restricted to patients who are at risk for metastatic disease. In this setting, the impact of 123I-MIBG scintigraphy on clinical decision-making appears very limited.

CT Characteristics of Pheochromocytoma: Relevance for the Evaluation of Adrenal Incidentaloma.

Background: Up to 7% of all adrenal incidentalomas (AIs) are pheochromocytomas (PCCs). In the evaluation of AI, it is generally recommended that PCC be excluded by measurement of plasma-free or 24-hour urinary fractionated metanephrines. However, recent studies suggest that biochemical exclusion of PCC not be performed for lesions with CT characteristics of an adrenocortical adenoma (ACA). Aim: To determine the proportion of PCCs with ACA-like attenuation or contrast washout on CT. Methods: For this multicenter retrospective study, two central investigators independently analyzed the CT reports of 533 patients with 548 histologically confirmed PCCs. Data on tumor size, unenhanced Hounsfield units (HU), absolute percentage washout (APW), and relative percentage washout (RPW) were collected in addition to clinical parameters. Results: Among the 376 PCCs for which unenhanced attenuation data were available, 374 had an attenuation of >10 HU (99.5%). In the two exceptions (0.5%), unenhanced attenuation was exactly 10 HU, which lies just within the range of ≤10 HU that would suggest a diagnosis of ACA. Of 76 PCCs with unenhanced HU > 10 and available washout data, 22 (28.9%) had a high APW and/or RPW, suggestive of ACA. Conclusion: Based on the lack of PCCs with an unenhanced attenuation of <10 HU and the low proportion (0.5%) of PCCs with an attenuation of 10 HU, it seems reasonable to abstain from biochemical testing for PCC in AIs with an unenhanced attenuation of ≤10 HU. The assessment of contrast washout, however, is unreliable for ruling out PCC.

Mouse Models of Primary Aldosteronism: From Physiology to Pathophysiology.

Primary aldosteronism (PA) is a common form of endocrine hypertension that is characterized by the excessive production of aldosterone relative to suppressed plasma renin levels. PA is usually caused by either a unilateral aldosterone-producing adenoma or bilateral adrenal hyperplasia. Somatic mutations have been identified in several genes that encode ion pumps and channels that may explain the aldosterone excess in over half of aldosterone-producing adenomas, whereas the pathophysiology of bilateral adrenal hyperplasia is largely unknown. A number of mouse models of hyperaldosteronism have been described that recreate some features of the human disorder, although none replicate the genetic basis of human PA. Animal models that reproduce the genotype-phenotype associations of human PA are required to establish the functional mechanisms that underlie the endocrine autonomy and deregulated cell growth of the affected adrenal and for preclinical studies of novel therapeutics. Herein, we discuss the differences in adrenal physiology across species and describe the genetically modified mouse models of PA that have been developed to date.

Changes in Body Mass Index in Pheochromocytoma Patients Following Adrenalectomy.

Catecholamine excess from pheochromocytoma results in cardiovascular symptoms such as arterial hypertension and tachycardia and induces metabolic alterations including glucose intolerance and increase in resting metabolic rate. The objective of our study was to investigate the effect of surgical cure of pheochromocytoma on body-mass-index and the correlation of body-mass-index changes to preoperative endocrine parameters. Pheochromocytoma patients from the Munich ENSAT Registry were matched (1:2) for age and gender to patients from the German Conn's Registry, who had undergone surgery for aldosterone-producing-adenomas. Thereby, 43 pheochromocytoma patients (17 males/26 females) and 86 aldosterone-producing-adenoma patients were analyzed for body-mass-index, blood pressure, and catecholamine levels before and one year after adrenalectomy. Seventy-four percent of pheochromocytoma patients were hypertensive preoperatively and 48% one year postoperatively. Systolic blood pressure did not differ significantly in pre- and postoperative measurements whereas diastolic blood pressure was significantly reduced over time. Moreover, pheochromocytoma patients gained body weight (p<0.001) one year following adrenalectomy accompanied by significant increases in body-mass-index, whereas aldosterone-producing adenoma patients displayed a slight weight loss. Despite weight gain, diagnosis of diabetes mellitus dropped from 9 of 43 investigated pheochromocytoma patients at baseline to 4 at follow-up. A significant correlation between body-mass-index changes to the preoperative catecholamine levels was found only for urinary normetanephrines. These data suggest that normalization of chronic catecholamine excess by adrenalectomy is associated with an increase in body-mass-index, which is more pronounced in patients with high preoperative levels of urinary normetanephrines.

Adrenal and Ovarian Phenotype of a Tissue-Specific Urocortin 2-Overexpressing Mouse Model.

Urocortin 2 (UCN2) is a neuropeptide of the CRH family, involved in homeostatic mechanisms, the stress response, and control of anxiety. To elucidate the effects of UCN2 on steroidogenesis, we developed a mouse model that allows a Cre recombinase-determined conditional overexpression of UCN2 (UCN2-COE). In these mice SF1-Cre-driven overexpression of UCN2 was restricted to the adrenal glands, gonads, and parts of the hypothalamus. UCN2-COE animals of both sexes revealed significantly higher plasma UCN2 levels and significantly higher UCN2 expression levels in the adrenals and ovaries. In contrast, the baseline expression of UCN2 was already high in the testes of control mice with no further increase achievable in UCN2-COE animals. Adrenal steroidogenesis of UCN2-COE animals was investigated under baseline conditions, upon an ACTH stimulation test, and following a restraint stress test. A tendency toward lower expression of steroidogenic enzymes was detectable in UCN2-COE animals of both sexes with slight differences between males and females. A similar reduction in the expression levels of the final steps of ovarian steroidogenesis, accompanied by reduced plasma estradiol levels, was observed in female UCN2-COE animals. Thus, adrenal UCN2 overexpression resulted in down-regulation of adrenal steroidogenesis, suggesting a reduction in the stress response in the mouse (stress coping behavior). Similarly, UCN2 overexpression in the ovaries caused a decrease in steroidogenesis and reduction of follicles that had undergone ovulation. Nevertheless, this finding was not associated with reduced fertility.

Diastrophic dysplasia sulfate transporter (SLC26A2) is expressed in the adrenal cortex and regulates aldosterone secretion.

Elucidation of the molecular mechanisms leading to autonomous aldosterone secretion is a prerequisite to define potential targets and biomarkers in the context of primary aldosteronism. After a genome-wide association study with subjects from the population-based Cooperative Health Research in the Region of Augsburg F4 survey, we observed a highly significant association (P=6.78×10(-11)) between the aldosterone to renin ratio and a locus at 5q32. Hypothesizing that this locus may contain genes of relevance for the pathogenesis of primary aldosteronism, we investigated solute carrier family 26 member 2 (SLC26A2), a protein with known transport activity for sulfate and other cations. Within murine tissues, adrenal glands showed the highest expression levels for SLC26A2, which was significantly downregulated on in vivo stimulation with angiotensin II and potassium. SLC26A2 expression was found to be significantly lower in aldosterone-producing adenomas in comparison with normal adrenal glands. In adrenocortical NCI-H295R cells, specific knockdown of SLC26A2 resulted in a highly significant increase in aldosterone secretion. Concomitantly, expression of steroidogenic enzymes, as well as upstream effectors including transcription factors such as NR4A1, CAMK1, and intracellular Ca(2+) content, was upregulated in knockdown cells. To substantiate further these findings in an SLC26A2 mutant mouse model, aldosterone output proved to be increased in a sex-specific manner. In summary, these findings point toward a possible effect of SLC26A2 in the regulation of aldosterone secretion potentially involved in the pathogenesis of primary aldosteronism.

Gender-, strain-, and inheritance-dependent variation in aldosterone secretion in mice.

Arterial hypertension represents one of the most common diseases in developed countries and the rennin-angiotensin-aldosterone system is among the major factors in the regulation of blood pressure and sodium balance. With the exception of rare monogenetic diseases, however, inheritance of aldosterone secretion is widely unknown. In this study, we investigated the aldosterone levels in male and female mice of two inbred strains, C3HeB/FeJ and C57BL/6J, as well as their offspring of the F1 and F2 generation. In all cases, female animals displayed lower aldosterone levels than males. Furthermore, C57BL/6J animals had significantly higher aldosterone levels than C3HeB/FeJ mice of the same age and gender. Depending on the paternal origin of the animal, the F1 offspring showed a tendency toward higher aldosterone values when the paternal side was from the C57BL/6J strain. This observation was confirmed in the F2 generation and over repeated measurements over three consecutive years. Quantification of the aldosterone to renin ratio in the different mouse groups did not show any significant differences, and, similarly, the determination of plasma potassium and kidney parameters did not provide any differences. On the molecular level, investigation of the expression of the enzymes involved in steroidogenesis displayed the same trend as for the aldosterone values, with animals hosting C57BL/6J background in their paternal origin having also the highest expression levels for StAR, cyp11a1, and cyp11b2 enzymes. Taken together, we could demonstrate that the genetic background of the animals plays a significant role modulating their plasma aldosterone levels without clear interference of other parameters in the renin-angiotensin-aldosterone system.