Aldosterone-induced oxidative stress: a potential mechanism of aldosterone autonomy in primary aldosteronism

Effects of Altered Calcium Metabolism on Cardiac Parameters in Primary Aldosteronism

BACKGROUND

Increasing evidence supports interplay between aldosterone and parathyroid hormone (PTH), which may aggravate cardiovascular complications in various heart diseases. Negative structural cardiovascular remodeling by primary aldosteronism (PA) is also suspected to be associated with changes in calcium levels. However, to date, few clinical studies have examined how changes in calcium and PTH levels influence cardiovascular outcomes in PA patients. Therefore, we investigated the impact of altered calcium homeostasis caused by excessive aldosterone on cardiovascular parameters in patients with PA.

METHODS

Forty-two patients (mean age 48.8±10.9 years; 1:1, male:female) whose plasma aldosterone concentration/plasma renin activity ratio was more than 30 were selected among those who had visited Severance Hospital from 2010 to 2014. All patients underwent adrenal venous sampling with complete access to both adrenal veins.

RESULTS

The prevalence of unilateral adrenal adenoma (54.8%) was similar to that of bilateral adrenal hyperplasia. Mean serum corrected calcium level was 8.9±0.3 mg/dL (range, 8.3 to 9.9). The corrected calcium level had a negative linear correlation with left ventricular end-diastolic diameter (LVEDD, ρ=-0.424, P=0.031). Moreover, multivariable regression analysis showed that the corrected calcium level was marginally associated with the LVEDD and corrected QT (QTc) interval (β=-0.366, P=0.068 and β=-0.252, P=0.070, respectively).

CONCLUSION

Aldosterone-mediated hypercalciuria and subsequent hypocalcemia may be partly involved in the development of cardiac remodeling as well as a prolonged QTc interval, in subjects with PA, thereby triggering deleterious effects on target organs additively.

Cardiac Dysfunction in Association with Increased Inflammatory Markers in Primary Aldosteronism

BACKGROUND

Oxidative stress in primary aldosteronism (PA) is thought to worsen aldosterone-induced damage by activating proinflammatory processes. Therefore, we investigated whether inflammatory markers associated with oxidative stress is increased with negative impacts on heart function as evaluated by echocardiography in patients with PA.

METHODS

Thirty-two subjects (mean age, 50.3±11.0 years; 14 males, 18 females) whose aldosterone-renin ratio was more than 30 among patients who visited Severance Hospital since 2010 were enrolled. Interleukin-1β (IL-1β), IL-6, IL-8, monocyte chemoattractant protein 1, tumor necrosis factor α (TNF-α), and matrix metalloproteinase 2 (MMP-2), and MMP-9 were measured. All patients underwent adrenal venous sampling with complete access to both adrenal veins.

RESULTS

Only MMP-2 level was significantly higher in the aldosterone-producing adenoma (APA) group than in the bilateral adrenal hyperplasia (BAH). Patients with APA had significantly higher left ventricular (LV) mass and A velocity, compared to those with BAH. IL-1β was positively correlated with left atrial volume index. Both TNF-α and MMP-2 also had positive linear correlation with A velocity. Furthermore, MMP-9 showed a positive correlation with LV mass, whereas it was negatively correlated with LV end-systolic diameter.

CONCLUSION

These results suggest the possibility that some of inflammatory markers related to oxidative stress may be involved in developing diastolic dysfunction accompanied by LV hypertrophy in PA. Further investigations are needed to clarify the role of oxidative stress in the course of cardiac remodeling.