Steroid Profiling and Immunohistochemistry for Subtyping and Outcome Prediction in Primary Aldosteronism-a Review

A comparison of the performance of 68Ga-Pentixafor PET/CT versus adrenal vein sampling for subtype diagnosis in primary aldosteronism

Objective

To investigate the diagnostic efficiency and prognostic value of 68Ga-Pentixafor PET/CT in comparison with adrenal vein sampling (AVS) for functional lateralization in primary aldosteronism (PA). Histology and long-term clinical follow-up normally serve as the gold standard for such diagnosis.

Methods

We prospectively recruited 26 patients diagnosed with PA. All patients underwent 68Ga-Pentixafor PET/CT and AVS. Postsurgical biochemical and clinical outcomes of patients with unilateral primary aldosteronism (UPA), as diagnosed by PET/CT or AVS, were assessed by applying standardized Primary Aldosteronism Surgical Outcome (PASO) criteria. Immunohistochemistry (IHC) was performed to detect the expression of aldosterone synthase (CYP11B2) and CXCR4.

Results

On total, 19 patients were diagnosed with UPA; of these, 13 patients were lateralized by both PET/CT and AVS, four patients were lateralized by PET-only, and two by AVS-only. Seven subjects with no lateralization on AVS and PET received medical therapy. All patients achieved complete biochemical success except one with nodular hyperplasia lateralized by AVS alone. The consistency between PET/CT and AVS outcomes was 77% (20/26). Moreover, CYP11B2-positive nodules were all CXCR4-positive and showed positive findings on PET. Patients who achieved complete biochemical and clinical success had a higher uptake on PET as well as stronger expression levels of CXCR4 and CYP11B2.

Conclusion

Our analysis showed that 68Ga-Pentixafor PET/CT could enable non-invasive diagnosis in most patients with PA and identify additional cases of unilateral and surgically curable PA which could not be classified by AVS. 68Ga-Pentixafor PET/CT should be considered as a first-line test for the future classification of PA.

Differential central regulatory mineralocorticoidreceptor systems for anxiety and depression - Could KCNJ5 be an interesting target for further investigations in major depression?

The mineralocorticoid receptor (MR) is suggested to play a role in the pathophysiology of depression and anxiety. Main support comes from studies in patients with primary aldosteronism (PA) which suggested different central pathways for depression and anxiety mediated via the MR and gender differences. We investigated 118 patients with PA over 3 years using self-rating questionnaires for anxiety (GAD-7) and depression (PHQD) at baseline and once a year under specific treatment with adrenalectomy (ADX; n = 48) or a MR antagonist (MRA; n = 70). Genotyping for KCNJ5 mutation was performed in resected tumors. At baseline, patients treated by ADX or MRA had comparable scores for anxiety and depression. Females showed a better metabolic profile but higher scores of depression and anxiety, compared to males. Initiation of specific treatment for PA resulted in a better response in depressive symptoms after ADX and of anxiety under MRA treatment. However, GAD-7 and PHQD remained high in women over the three-year follow-up. KCNJ5 mutation, linked to co-secretion of hybrid steroids as 18-oxocortisol and 18-hydroxycortisol, was detected in 10 female and 2 male patients. They tended to have higher GAD and PHQD scores at baseline compared to patients without KNCJ5 mutation, but showed a significant better reduction in symptoms of anxiety during the 3-year follow up compared to patients without this mutation (all p < 0.05). These data support a differentiated regulation of depression and anxiety by the MR. Moreover, genetic mutations such as KCNJ5 could affect the pathophysiology of these disorders by impacting in adrenal steroidogenesis.

Clinical Translationality of KCNJ5 Mutation in Aldosterone Producing Adenoma

Hypertension due to primary aldosteronism poses a risk of severe cardiovascular complications compared to essential hypertension. The discovery of the KCNJ5 somatic mutation in aldosteroene producing adenoma (APA) in 2011 and the development of specific CYP11B2 antibodies in 2012 have greatly advanced our understanding of the pathophysiology of primary aldosteronism. In particular, the presence of CYP11B2-positive aldosterone-producing micronodules (APMs) in the adrenal glands of normotensive individuals and the presence of renin-independent aldosterone excess in normotensive subjects demonstrated the continuum of the pathogenesis of PA. Furthermore, among the aldosterone driver mutations which incur excessive aldosterone secretion, KCNJ5 was a major somatic mutation in APA, while CACNA1D is a leading somatic mutation in APMs and idiopathic hyperaldosteronism (IHA), suggesting a distinctive pathogenesis between APA and IHA. Although the functional detail of APMs has not been still uncovered, its impact on the pathogenesis of PA is gradually being revealed. In this review, we summarize the integrated findings regarding APA, APM or diffuse hyperplasia defined by novel CYP11B2, and aldosterone driver mutations. Following this, we discuss the clinical implications of KCNJ5 mutations to support better cardiovascular outcomes of primary aldosteronism.

Reliability Analysis of a Functional Diagnostic Test for Primary Hyperaldosteronism Based on Data Analysis

Primary aldosteronism (PA) is one of the most common causes of secondary hypertension, with a prevalence of 12-20% in the hypertensive population. To determine the characteristic function of a fuzzy concept based on the epidemiological data, clinical manifestations, and auxiliary examinations of PA, the essence is to select a suitable domain and determine the affiliation of each element in the domain. The aldosterone/renin ratio was proposed to increase the detection rate of PA, which has the shortcoming of a high underdiagnosis rate when relying only on clinical manifestations. However, there is no unified standard for the diagnostic cut point, and there are differences in testing methods and diagnostic cut point values for different populations, which require different laboratories to establish appropriate cut points according to different regional populations to improve the diagnostic accuracy. In this article, we analyzed the reliability of functional diagnostic tests for PA based on data analysis and compared the sensitivity and specificity of different plasma aldosterone cut points for the diagnosis of PA in the 40 mg kibbutz test. The results showed that when post-saline PAC and post-cato PAC were used to confirm the diagnosis of proaldosterone, respectively, there was a similar subject working area under the curve between SSST and CCT, 0.89 and 0.78, respectively, with no significant difference in the area under the curve between the two (p=0.546). Therefore, blood sodium and blood potassium have higher specificity and sensitivity than SUSPUP, but both are lower than ARR, and data analysis can be used as an auxiliary indicator for screening.

[Conn's syndrome-Frequent and still too rarely diagnosed to underdiagnosed]

Conn's syndrome represents the most common cause of endocrine hypertension and is associated with an increased cardiovascular risk, a series of comorbidities (including type 2 diabetes mellitus) and with their frequent occurrence. Therefore, a correct and rapid diagnosis is of essential importance. Measurement of the aldosterone-renin ratio is used as a first screening test for primary aldosteronism. This should ideally be evaluated under optimized conditions (e.g. at rest), after adjustment of the blood pressure medication and with an equilibrated potassium balance. In cases of elevated aldosterone to renin ratio, further confirmatory testing as well as imaging of the adrenal glands is needed. After confirmation of Conn's syndrome a differentiation between a unilateral and bilateral adrenal disease is necessary for further treatment planning. The current gold standard is still selective adrenal vein catheterization. Promising alternatives to an adrenal vein catheter, such as functional imaging techniques and measurement of steroid profiles are currently being investigated in clinical trials. In cases of lateralization of aldosterone production, unilateral laparoscopic adrenalectomy of the affected side is the treatment of choice. In contrast, patients with bilateral disease or patients with contraindications for adrenalectomy should receive life-long treatment with mineralocorticoid receptor antagonists.

Long-chain noncoding RNA-GAS5/hsa-miR-138-5p attenuates high glucose-induced cardiomyocyte damage by targeting CYP11B2

OBJECTIVE

Diabetic cardiomyopathy (DCM) is one of the complications experienced by patients with diabetes. In recent years, long noncoding RNAs (lncRNAs) have been investigated because of their role in the progression of various diseases, including DCM. The purpose of the present study was to explore the role of lncRNA GAS5 in high glucose (HG)-induced cardiomyocyte injury and apoptosis.

MATERIALS AND METHODS

We constructed HG-induced AC16 cardiomyocytes and a streptozotocin (STZ)-induced rat diabetes model. GAS5 was overexpressed and knocked out at the cellular level, and GAS5 was knocked down by lentiviruses at the animal level to observe its effect on myocardial injury. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression of GAS5. Cell proliferation and apoptosis after GAS5 knockout were detected by CCK-8, TUNEL, and flow cytometry assays. ELISA was used to detect the changes in myocardial enzyme content in cells and animal myocardial tissues during the action of GAS5 on myocardial injury.

RESULTS

GAS5 expression was up-regulated in HG-treated AC16 cardiomyocytes and the rat diabetic myocardial injury model. The down-regulation of GAS5 could inhibit HG-induced myocardial damage. This work proved that the down-regulation of GAS5 could reverse cardiomyocyte injury and apoptosis by targeting miR-138 to down-regulate CYP11B2.

CONCLUSION

We confirmed for the first time that the down-regulation of GAS5 could reverse CYP11B2 via the miR-138 axis to reverse HG-induced cardiomyocyte injury. This research might provide a new direction for explaining the developmental mechanism of DCM and potential targets for the treatment of myocardial injury.

Urine steroid profile as a new promising tool for the evaluation of adrenal tumors. Literature review

PURPOSE

To review the literature assessing the diagnostic performance of urinary steroid profiling (USP) by high-performance liquid chromatography (LC-MS) or gas chromatography (GC) coupled to mass spectrometry (MS) in the evaluation of adrenal lesions, both in terms of functionality and malignancy.

RESULTS

The evaluation of adrenal incidentalomas (AI) aims to rule out malignancy and hormone excess. Current diagnostic protocols have several limitations and include time consuming and relatively complicated multi-step processes in most cases. On the contrary, USP by LC-MS/MS or LC-GC/MS offer an easy, comprehensive and non-invasive assessment of adrenal steroid secretion. USP complements current workups used in the evaluation of AIs by improving our ability to identify malignancy and/or autonomous hormone secretion.

CONCLUSIONS

Urine steroid profiling by LC-MS/MS and GC-MS allows a thorough, non-invasive, assessment of adrenal steroidogenesis as a whole which complement the current evaluation of AIs, and holds a promising role in the diagnosis of autonomous cortisol secretion, primary aldosteronism, and adrenal malignancy.

Adrenal Venous Sampling-Guided Adrenalectomy Rates in Primary Aldosteronism: Results of an International Cohort (AVSTAT)

CONTEXT

Adrenal venous sampling (AVS) is the current criterion standard lateralization technique in primary aldosteronism (PA). Japanese registry data found that 30% of patients with unilateral PA did not undergo adrenalectomy, but the reasons for this and whether the same pattern is seen internationally are unknown.

OBJECTIVE

To assess the rate of AVS-guided adrenalectomy across an international cohort and identify factors that resulted in adrenalectomy not being performed in otherwise eligible patients.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective, multinational, multicenter questionnaire-based survey of management of PA patients from 16 centers between 2006 and 2018.

MAIN OUTCOME MEASURES

Rates of AVS implementation, AVS success rate, diagnosis of unilateral PA, adrenalectomy rate, and reasons why adrenalectomy was not undertaken in patients with unilateral PA.

RESULTS

Rates of AVS implementation, successful AVS, and unilateral disease were 66.3%, 89.3% and 36.9% respectively in 4818 patients with PA. Unilateral PA and adrenalectomy rate in unilateral PA were lower in Japanese than in European centers (24.0% vs 47.6% and 78.2% vs 91.4% respectively). The clinical reasoning for not performing adrenalectomy in unilateral PA were more likely to be physician-derived in Japan and patient-derived in Europe. Physician-derived factors included non-AVS factors, such as good blood pressure control, normokalemia, and the absence of adrenal lesions on imaging, which were present before AVS.

CONCLUSION

Considering the various unfavorable aspects of AVS, stricter implementation and consideration of surgical candidacy prior to AVS will increase its diagnostic efficiency and utility.

Confirmatory testing of primary aldosteronism with saline infusion test and LC-MS/MS

OBJECTIVE

Saline infusion testing (SIT) for confirmation of primary aldosteronism (PA) is based on impaired aldosterone suppression in PA compared to essential hypertension (EH). In the past, aldosterone was quantified using immunoassays (IA). Liquid chromatography tandem mass spectrometry (LC-MS/MS) is increasingly used in clinical routine. We aimed at a method-specific aldosterone threshold for the diagnosis of PA during SIT and explored the diagnostic utility of steroid panel analysis.

DESIGN

Retrospective cohort study of 187 paired SIT samples (2009-2018). Diagnosis of PA (n = 103) and EH (n = 84) was established based on clinical routine workup without using LC-MS/MS values.

SETTING

Tertiary care center.

METHODS

LC-MS/MS using a commercial steroid panel. Receiver operator characteristics analysis was used to determine method-specific cut-offs using a positive predictive value (PPV) of 90% as criterion.

RESULTS

Aldosterone measured by IA was on average 31 ng/L higher than with LC-MS/MS. The cut-offs for PA confirmation were 54 ng/L for IA (sensitivity: 95%, 95% CI: 89.0-98.4; specificity: 87%, 95% CI: 77.8-93.3; area under the curve (AUC): 0.955, 95% CI: 0.924-0.986; PPV: 90%, 95% CI: 83.7-93.9) and 69 ng/L for LC-MS/MS (79%, 95% CI: 69.5-86.1; 89%, 95% CI: 80.6-95.0; 0.902, 95% CI: 0.857-0.947; 90%, 95% CI: 82.8-94.4). Other steroids did not improve SIT.

CONCLUSIONS

Aldosterone quantification with LC-MS/MS and IA yields comparable SIT-cut-offs. Lower AUC for LC-MS/MS is likely due to the spectrum of disease in PA and previous decision making based on IA results. Until data of a prospective trial with clinical endpoints are available, the suggested cut-off can be used in clinical routine.

Surgical Outcomes of Aldosterone-Producing Adenoma on the Basis of the Histopathological Findings

INTRODUCTION

Previous studies on the surgical outcomes of aldosterone-producing adenoma (APA) patients were mainly based on the histopathological diagnosis of HE staining or adrenal venous sampling (AVS) instead of the functional pathology. The aim of the present study was to evaluate the surgical outcomes of APA patients based on the functional pathological diagnosis of APA according to HISTALDO (histopathology of primary aldosteronism) consensus.

METHODS

Clinical data of 137 patients with suspected APA were analyzed retrospectively. All patients had hypertension and spontaneous hypokalemia. In all patients, CT showed a unilateral solitary hypodense adrenal lesion, and a contralateral adrenal gland of normal morphology. Tumors were removed and immunostained for CYP11B2, and their pathology were identified based on HISTALDO consensus. Patients were followed up 6 to 24 months after operation.

RESULTS

Among 137 cases of presumptive APA diagnosed by CT, 130 (95%) cases were pathologically diagnosed with classical pathology, including 123 APA(90%) and 7 aldosterone-producing nodule (APN) (5%). 7 cases (5%) had non-functioning adenoma (NFA) with aldosterone-producing micronodule (APM) or multiple aldosterone-producing micronodule (MAPM) in the surrounding adrenal tissue. In all 137 patients, hypertension was complete or partial clinical success postoperatively. Complete clinical success was achieved in 73 (53%), and partial clinical success was achieved in 64 (47%) cases. Serum potassium level recovered to normal in all. In 123 patients with APA, complete clinical success was reached in 67 (54%), and partial clinical success was reached in 56 (46%) cases. Gender, duration of hypertension and the highest SBP were significant independent predictors for cure of APA after surgery. A multiple logistic regression model integrating the three predictors was constructed to predict the outcome, which achieved a sensitivity of 72.4% and a specificity of 73.1%.

CONCLUSION

The specificity of CT in the diagnosis of APA and APN patients with hypokalemia was 95%. All patients achieved complete or partial clinical success after surgery. Gender, duration of hypertension and the highest SBP were independent predictors for the postoperative cure of APA.

The Potential of Steroid Profiling by Mass Spectrometry in the Management of Adrenocortical Carcinoma

Radiological and endocrinological work up of adrenal neoplasms is aimed at distinguishing between frequent non-functioning adenomas and rare but very aggressive adrenocortical carcinoma (ACC). Relevant research has addressed the identification of molecular, genetic and hormonal markers that could have clinical significance for malignancy, as well as a prognostic value. Regarding endocrine aspects, attention has been paid to the pattern of steroid secretion that can be affected by altered steroidogenic pathway in ACC. The advent of mass spectrometry techniques has overcome many limitations usually associated with immunoassays, allowing the determination of both common and rarely measured steroids in a single analysis with high specificity and sensitivity. Indeed, mass spectrometry strategies may be able to identify an individualized steroid profile of ACC, allowing a rapid diagnosis and a specific follow-up. In this review, insights, strengths and limitations of mass spectrometry-based approaches in steroid profiling, as well as of immunoassay in steroid measurements, will be specifically discussed. Moreover, the latest findings on steroid profiling by mass spectrometry-based techniques, the most promising analytical tool, will be summarized to evaluate if steroid profiling might be the clue for solving the clinical dilemma in differentiating ACC from non-functioning adrenocortical adenomas (ACA).

The Potential Role of Aldosterone-Producing Cell Clusters in Adrenal Disease

Primary aldosteronism (PA) is the most common cause of secondary hypertension. The hallmark of PA is adrenal production of aldosterone under suppressed renin conditions. PA subtypes include adrenal unilateral and bilateral hyperaldosteronism. Considerable progress has been made in defining the role for somatic gene mutations in aldosterone-producing adenomas (APA) as the primary cause of unilateral PA. This includes the use of next-generation sequencing (NGS) to define recurrent somatic mutations in APA that disrupt calcium signaling, increase aldosterone synthase (CYP11B2) expression, and aldosterone production. The use of CYP11B2 immunohistochemistry on adrenal glands from normal subjects, patients with unilateral and bilateral PA has allowed the identification of CYP11B2-positive cell foci, termed aldosterone-producing cell clusters (APCC). APCC lie beneath the adrenal capsule and like APA, many APCC harbor somatic gene mutations known to increase aldosterone production. These findings suggest that APCC may play a role in pathologic progression of PA. Herein, we provide an update on recent research directed at characterizing APCC and also discuss the unanswered questions related to the role of APCC in PA.

Primary aldosteronism diagnostics: KCNJ5 mutations and hybrid steroid synthesis in aldosterone-producing adenomas

Primary aldosteronism (PA) is characterized by autonomous aldosterone production by renin-independent mechanisms and is most commonly sporadic. While 60-70% of sporadic PA can be attributed to bilateral hyperaldosteronism, the remaining 30-40% is caused by a unilateral aldosterone-producing adenoma (APA). Somatic mutations in or near the selectivity filter the KCNJ5 gene (encoding the potassium channel GIRK4) have been implicated in the pathogenesis of both sporadic and familial PA. Several studies using tumor tissue, peripheral and adrenal vein samples from PA patients have demonstrated that along with aldosterone, the hybrid steroids 18-hydroxycortisol (18OHF) and 18-oxocortisol (18oxoF) are a hallmark of APA harboring KCNJ5 mutations. Herein, we review the recent advances with respect to the molecular mechanisms underlying the pathogenesis of PA and the steroidogenic fingerprints of KCNJ5 mutations. In addition, we present an outlook toward the future of PA subtyping and diagnostic work-up utilizing steroid profiling.

Primary aldosteronism

Primary aldosteronism (PA) is a common cause of secondary hypertension caused by excessive and inappropriate secretion of the hormone aldosterone from one or both adrenal glands. The prevalence of PA ranges from 10% in the general hypertensive population to 20% in resistant hypertension, yet only a small fraction of patients is diagnosed. Disease and symptom recognition, screening in indicated populations, multidisciplinary communication, and appropriate imaging and biochemical workup can identify patients who might benefit from effective and targeted treatment modalities. Effective treatments available include both surgical and medical approaches, usually dependent on the subtype of PA present. Our collective understanding of the pathophysiology of PA is expanded by recent developments in molecular biology and genetics, including understanding the specific somatic and germline mutations involved in pathogenesis. We review the pathophysiology, diagnostic workup, and treatment considerations for this disease process.