Tumor size of Conn's adenoma and comorbidities

Characterization of a Biochemical Mouse Model of Primary Aldosteronism for Thermal Therapies

Introduction

Aldosterone-producing adenoma (APA) is the most common cause of endocrine-related hypertension but surgery is not always feasible. Current medical interventions are associated with significant side effects and poor patient compliance. New APA animal models that replicate basic characteristics of APA and give physical and biochemical feedback are needed to test new non-surgical treatment methods, such as image-guided thermal ablation.

Methods

A model of APA was developed in nude mice using HAC15 cells, a human adrenal carcinoma cell line. Tumor growth, aldosterone production, and sensitivity to angiotensin II were characterized in the model. The utility of the model was validated via treatment with microwave ablation and characterization of the resulting physical and biochemical changes in the tumor.

Results

The APA model showed rapid and relatively homogeneous growth. The tumors produced aldosterone and steroid precursors in response to angiotensin II challenge, and plasma aldosterone levels were significantly higher in tumor bearing mice two hours after challenge verses non-tumor bearing mice. The model was useful for testing microwave ablation therapy, reducing aldosterone production by 80% in treated mice.

Conclusion

The HAC15 model is a useful tumor model to study and develop localized treatment methods for APA.

Simple standing test without furosemide is useful in the diagnosis of primary aldosteronism

Primary aldosteronism (PA) is a well-known cause of secondary hypertension. We have long performed the simple standing test in patients with PA. On the other hand, there are few reports on the usefulness of the simple standing test in PA. This study is a single-center, retrospective, observational study. A total of 173 patients with hypertension or adrenal tumor admitted to Kawasaki Medical School were included. Eighty patients who met the exclusion criteria were excluded, and 31 patients without PA (non-PA), 26 patients with unilateral PA, and 36 patients with bilateral PA were included in the study. The simple standing test was performed after 120 min of standing or sitting followed, and the aldosterone/renin ratio (ARR) and percentage of increase plasma aldosterone concentration (%increase of PAC) was calculated. The mean ARR in the simple standing test in unilateral PA (1143 (528-2200)) and bilateral PA subjects (521 (374-765)) were significantly higher compared to non-PA subjects (152 (102-240)) (p < 0.0001, p = 0.0013, respectively). The percentage increase of PAC after standing loading was significantly lower in unilateral PA subjects (110 (96-140)) compared to non-PA subjects (187 (155-244)) (p = 0.0003), with no difference between non-PA and bilateral PA subjects (p = 0.99). The cutoff value of the ARR in the simple standing test for diagnosis of PA in this study was 364 (AUC = 0.948, sensitivity = 83.8%, specificity = 93.5%, false positive rate = 3.7%, false negative rate = 25.6%, p < 0.001), which was not inferior to the diagnostic performance of the captopril loading test. The diagnostic performance of the simple standing test for PA was not inferior to that of the captopril loading test. The percentage increase of PAC in unilateral PA subjects was significantly lower compared to bilateral PA subjects. These results demonstrate the usefulness of the simple standing test, which can be performed simultaneously with general screening tests of PA.

Aldosterone-Producing Adenomas of Increased Size Are Associated With Higher Steroidogenic Activity

CONTEXT

There are inconsistent results and insufficient evidence as to whether an association exists between the size and aldosterone-producing ability of aldosterone-producing adenomas.

OBJECTIVE

We further investigated this possible association retrospectively.

METHODS

A total of 142 cases of primary aldosteronism diagnosed as unilateral by adrenal venous sampling at 2 referral centers between 2009 and 2019 were included. We classified these individuals into small and large tumor groups using a diameter of 14 mm as a cutoff. This size was the median diameter of the tumor on the affected side of the adrenal gland. We compared plasma aldosterone concentration (PAC), plasma renin activity (PRA), PAC to PRA ratio, PAC from a saline infusion test (SIT), urinary aldosterone secretion (uAld), and serum potassium as indices of aldosterone-producing ability between the 2 groups. In some cases, we conducted histopathological evaluations and detection of the KCNJ5 mutation.

RESULTS

PAC, PAC to PRA ratio, PAC from SIT, and uAld were higher and serum potassium was lower in the large tumor group. PAC, PAC from SIT, uAld, and serum potassium significantly correlated with tumor diameter. PRA was not associated with tumor diameter. Clear cell-dominant cases were more common in the large tumor group, while cases showing a strong expression of CYP11B2 were not significantly different between the groups. KCNJ5 mutations tended to be more common in the large tumor group.

CONCLUSION

The higher aldosterone-producing ability in larger adenomas can be used to infer the responsible lesion and disease type.

Sleep quality in patients with primary aldosteronism

OBJECTIVE

In subjects at high risk for sleep apnea (SA), aldosterone concentrations correlate with severity of SA and primary aldosteronism (PA) is very often diagnosed. Patients with PA show a high prevalence of SA. Treatment of PA either by adrenalectomy (ADX) or mineralocorticoid receptor (MR) blockade is thought to abolish the increased comorbidities. However, no data are available regarding effectiveness of different PA treatments on quality of sleep.

DESIGN

This prospective multi-center study included 15 patients with newly diagnosed PA evaluated before and 0.7 ± 0.2 years after treatment initiation, and a second cohort including 81 patients who were evaluated 5.3 and 6.8 years after treatment initiation. Biochemical parameters, 24h blood pressure and three validated self-assessment questionnaires (Giessen Complaint List (GBB-24), Epworth Sleepiness Scale (ESS) and Pittsburgh Sleep Quality-Index (PSQI)) were analyzed.

RESULTS

Z-scores of exhaustion tendency of GBB significantly improved in newly diagnosed PA patients after treatment initiation (1.8 ± 1.4 vs. 1.0 ± 1.2, p=0.034). In the second cohort no differences were found in GBB-24, ESS and PSQI. No differences were found in all three questionnaires independently of type of PA therapy. However, female patients scored significantly higher than males in the PSQI (8.7 ± 3.6 vs 5.7 ± 4.2, p<0.005), indicating lower sleep quality, independently of the type of therapy.

CONCLUSIONS

For the first time, we analyzed quality of sleep in patients with PA, demonstrating that therapy initiation improves exhaustion tendency. Surprisingly, female PA patients showed significantly more sleep disturbances than male PA patients several years after treatment initiation.

Serum dehydroepiandrosterone sulfate concentration is lower in women with primary aldosteronism

OBJECTIVE

The objective of this article is to measure serum dehydroepiandrosterone sulfate (DHEA-S) concentration in both genders with primary aldosteronism (PA).

MATERIALS AND METHODS

The study enrolled 78 subjects with normal controls, 46 subjects with essential hypertension and 85 subjects with PA from October 2007 to June 2011. Subjects with PA were divided into three subtype groups: aldosterone-producing adenoma (APA), bilateral idiopathic hyperplasia (IHA) and PA with negative imaging findings.

RESULTS

Women with PA (n = 49) had lower serum DHEA-S levels compared with normal controls and subjects with essential hypertension (p < 0.01). In subtype analysis, only female APAs had lower serum DHEA-S levels (p < 0.01 compared with normal controls, p < 0.01 compared with subjects with essential hypertension). In APA, a significant correlation between tumor size and serum DHEA-S was found in women (p < 0.01).

CONCLUSION

Our data suggested that serum DHEA-S levels are lower in women with PA. In subtype groups, only women with APA had lower serum DHEA-S. There was no significant difference between subjects with bilateral essential hyperplasia, PA with negative imaging findings, normal controls and subjects with essential hypertension in both genders. The serum DHEA-S level is negatively correlated with the size of APA.

Female sex hormones are associated with the reduction of serum sodium and hypertension complications in patients with aldosterone-producing adenoma

This study was conducted to evaluate gender-related differences in clinical characteristics and vascular complications in patients with aldosterone-producing adenomas (APA). Clinical characteristics, biochemical markers and incidence of vascular complications were compared by gender in 187 consecutive patients with APA confirmed by pathological diagnosis. Patients were separated into two groups based on ages either older or younger than 49 years, the average age of menopause among Chinese women (<49 y and ≥49 y). Males had significantly higher BMI than females in the age group of <49 years (p = 0.017). In the <49 years group, males had significantly higher serum sodium levels (p = 0.003). However, no such gender differences in clinical characteristics were observed in patients ≥49 years. A higher proportion of vascular complications was observed in males as compared to females aged <49 years but the difference was not statistically significant (51.4% vs. 34.8%, p = 0.105). The only gender difference observed in vascular complications between patients aged ≥49 years was that a significantly greater proportion of males had cerebrovascular complication compared to females (p = 0.006). Our data suggest that female sex hormones are implicated in reducing serum sodium concentration and vascular complications in female APA patients.

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.

Clinical characteristics of primary hyperaldosteronism due to adrenal microadenoma

An increasing number of patients are being diagnosed with primary aldosteronism (PA) due to aldosterone-producing macroadenoma (APA). However, there are only limited data available on the clinical characteristics of PA that are associated with adrenal microadenoma. Of the 55 patients that were diagnosed with PA in our study, 22 patients showed a unilateral adrenal over-production of aldosterone. The histopathology of the surgically removed adrenal tissues led to six patients being diagnosed with microadenoma, and the clinical features of microadenoma, macroadenoma and idiopathic hyperaldosteronism (IHA) were studied. The expression levels of CYP11B2, CYP17, CYP21 and 3β-hydroxysteroid dehydrogenase 2 (HSD3B2) mRNA in the adrenal cortices (n=5 and 6, respectively) that remained attached to the adrenal microadenomas or macroadenomas were examined by real time-PCR and then compared to the expression levels in the adrenal cortices (n=5) of non-functioning adrenal adenomas (NF). The patients with microadenoma (n=6) had significantly higher diastolic blood pressure than the patients with macroadenoma (n=16) or IHA (n=33) (p<0.05). The systolic blood pressure, plasma aldosterone concentration, serum potassium level and renal function did not differ between the PA sub-groups. The levels of CYP11B2 and CYP17 mRNA were significantly increased in the adjacent tissues of microadenomas, as compared with macroadenomas or NF (p<0.05), whereas no significant differences in the CYP21 and HSD3B2 mRNA levels were found between the PA sub-groups. The tumor size did not influence the clinical characteristics of APA. The non-tumor portions of the microadenomas showed marked and sustained CYP11B2 mRNA expression under the suppressed renin-angiotensin system. We suggest that an increased number of microadenomas should be sampled, and the immunohistochemistry for steoridogenic enzymes should be investigated to clarify the etiology of microadenoma.

Progress in primary aldosteronism: present challenges and perspectives

Primary Aldosteronism (PA) is a disorder of the adrenal zona glomerulosa (ZG) in which aldosterone secretion is increased and is relatively autonomous of normal regulatory mechanisms. A recent conference in Munich organized by Prof. Reincke addressed advances and challenges related to the screening, diagnosis, and identification of uni- and bilateral involvement of the diseased adrenal of PA. Some infrequently addressed issues are described herein. We postulate that most cases of PA are due to the activation by unknown mechanisms of subset of cells resulting in the formation of a multiple foci or nodules of hyperactive zona glomerulosa cells. This implies that one or several yet unidentified stimuli can drive aldosterone overproduction, as well as the proliferation of aldosterone-producing cells. Current diagnostic procedures allow to determine whether inappropriate aldosterone production is driven by one or both adrenal glands and thus to establish optimal treatment.