Aldosterone escape

Abstract: It has been reported that continuous ACE inhibitor therapy does not necessarily produce a maintained decrease in plasma aldosterone levels, which may remain high or increase eventually during long-term use (aldosterone escape). We have examined the role of aldosterone escape in 45 patients with type 2 diabetes and early nephropathy treated with an ACE inhibitor for 40 weeks. With treatment, there was a 40% reduction in average urinary albumin excretion, although urinary albumin excretion in patients with aldosterone escape (18 patients) was significantly higher than that in patients without escape (27 patients). In the 18 patients with escape, spironolactone (25 mg/d) was added to ACE inhibitor treatment in 13. After a 24-week study period, urinary albumin excretion and left ventricular mass index were significantly reduced without blood pressure change. In conclusion, the present study demonstrates that aldosterone escape is observed in 40% of patients with type 2 diabetes with early nephropathy despite the use of ACE inhibitors. Our study suggests the possibility that aldosterone blockade may represent optimal therapy for patients with early diabetic nephropathy who show aldosterone escape during ACE inhibitor treatment and who no longer show maximal antiproteinuric effects of ACE inhibition. Additional, larger, prospectively randomized, double-blind studies will be needed before adaptation of this strategy.

Abstract: Interruption of the renin-angiotensin-aldosterone system has become a leading therapeutic strategy in the treatment of chronic heart and kidney disease. Angiotensin-converting-enzyme inhibitors and angiotensin-receptor blockers do not, however, uniformly suppress the renin-angiotensin-aldosterone system. Plasma aldosterone levels are elevated in a subset of patients despite therapy. This phenomenon, known as 'aldosterone escape' or 'aldosterone breakthrough', has only been directly examined in small numbers of patients. The key questions of how often breakthrough occurs and whether breakthrough leads to worse outcomes have yet to be definitively answered. In this Review, we summarize the reported data on the incidence and clinical implications of aldosterone breakthrough, and highlight areas of uncertainty that have yet to be adequately addressed in the literature. Although the available evidence is not strong enough to support widespread screening for aldosterone breakthrough, our findings should prompt physicians to consider the phenomenon in select patients as well as guide future research efforts.

Abstract: It has been suggested that aldosterone plays a role in the initiation and progression of renal disease independently of arterial blood pressure and plasma angiotensin II levels. We evaluated the influence of plasma aldosterone levels on progression of diabetic nephropathy during long-term blockade of the renin–angiotensin–aldosterone system. A total of 63 hypertensive patients with type 1 diabetes and diabetic nephropathy were treated with losartan, 100 mg once daily, for a mean follow-up period of 35 months. Plasma aldosterone, GFR, albuminuria and 24-h blood pressure were determined at baseline and at regular intervals during the study. Patients were divided according to their increasing or decreasing levels of plasma aldosterone during long-term losartan treatment in an escape group (n=26) and a non-escape group (n=37). In the escape group, aldosterone levels increased from (geometric mean [95% CI]) 57 pg/ml (43–76 pg/ml) at 2 months, to 102 pg/ml (78–134 pg/ml) at the end of the study (p<0.01). The corresponding levels in the non-escape group were 83 pg/ml (69–102 pg/ml) and 49 pg/ml (40–60 pg/ml; p<0.01). The median rate of decline in GFR was 5.0 ml·min−1·year−1 (range 0.4–15.9 ml·min−1·year−1) in the escape group, compared with 2.4 ml·min−1·year−1 (−1.6 to 11.0 ml·min−1·year−1) in the non-escape group (p<0.005). The increase in plasma aldosterone correlated with the rate of decline in GFR (r 2=0.19, p<0.001), corresponding to a decline in GFR of 1.5 ml·min−1·year−1 for every two-fold increase in plasma aldosterone. Pre-treatment and treatment values of plasma aldosterone were not related to albuminuria or to changes in albuminuria during the study. Our data suggest that aldosterone escape during long-term blockade of the renin–angiotensin–aldosterone system is associated with an enhanced decline in GFR in patients with type 1 diabetes and diabetic nephropathy.

Abstract: The renin-angiotensin-aldosterone system plays a central role in the development of hypertension and the progression of end-organ damage. Although angiotensin-converting enzyme inhibitors and angiotensin II receptor antagonists can initially suppress plasma aldosterone, it is now well established that aldosterone escape may occur, whereby aldosterone levels return to or exceed baseline levels. The classic effects of aldosterone relate mainly to its action on epithelial cells to regulate water and electrolyte balance. However, blood pressure reduction or fluid loss could not account for the results of the Randomized Aldactone Evaluation Study, which showed that a low dose of spironolactone in addition to conventional therapy could decrease the overall risk of mortality by 30% among patients with severe congestive heart failure. The action of aldosterone at nonepithelial sites in the brain, heart, and vasculature is consistent with the presence of mineralocorticoid receptors in these tissues. Aldosterone has a number of deleterious effects on the cardiovascular system, including myocardial necrosis and fibrosis, vascular stiffening and injury, reduced fibrinolysis, endothelial dysfunction, catecholamine release, and production of cardiac arrhythmias. Several studies have now shown vascular and target-organ protective effects of aldosterone receptor antagonism in the absence of significant blood pressure lowering, consistent with a major role for endogenous mineralocorticoids as mediators of cardiovascular injury. The advent of selective aldosterone receptor antagonists such as eplerenone should prove of great therapeutic value in the prevention of cardiovascular disease and associated end-organ damage.