HUMAN RED BLOOD CELLS ALTERATIONS IN PRIMARY ALDOSTERONISM.

Context:Aldosterone (Aldo) effects include NADPH-oxidase activation involved in Aldo-related oxidative stress. Red blood cells (RBC) are particularly sensitive to oxidative assault and both the association in high molecular weight aggregates (HMWA) and diamide-induced Tyr-phosphorylation (Tyr-P) level of membrane band 3 can be used to monitor their redox status.Objective:Erythrocytes' Aldo-related alterations were evaluated by comparing in vitro evidence.Design:Multicenter comparative study.Study Participants:The study included 12 patients affected by Primary Aldosteronism (PA) and 6 healthy controls (HC), whose RBC were compared with those of PA patients. For in vitro experiments HC-RBC were incubated with increasing Aldo concentrations.Main Outcome Measures:Tyr-P level, band 3 HMWA formation and autologous IgG binding were evaluated.Results:In PA, both Tyr-P levels and band 3 HMWA were higher than in controls.HC-RBC were treated with increasing Aldo concentrations in both platelet poor plasma (PPP) and charcoal-stripped (CS)-PPP. Results showed that Aldo had dose- and time-dependent effects on band 3 Tyr-P and HMWA formation, in CS-PPP more than in PPP. These effects were almost completely prevented by canrenone (Can) or cortisol (Cort). Aldo-related membrane alterations led to increased autologous IgG binding.Conclusion:Erythrocytes from PA patients show oxidative-like stress evidenced by increased HMWA content and diamide-induced band 3 Tyr-P level. Aldo effects are mediated by mineralocorticoid receptor, as suggested by the inhibitory effects of Can, antagonist of Aldo. In CS-PPP, where Aldo induces remarkable membrane alterations leading to IgG binding, Aldo may be responsible for premature RBC removal from circulation.