Aldosterone Induces Vasoconstriction In Individuals With Type 2 Diabetes: Effect Of Acute Antioxidant Administration

Context: Individuals with type 2 diabetes have an increased risk of endothelial dysfunction and cardiovascular disease. Plasma aldosterone could contribute by reactive oxygen species-dependent mechanisms by inducing a shift in the balance between a vasoconstrictor and vasodilator response to aldosterone.Objective: We aimed to investigate the acute vascular effects of aldosterone in individuals with type 2 diabetes compared with healthy controls and if infusion of an antioxidant (n-acetylcysteine [NAC]) would alter the vascular response.Methods: In a case-control design, 12 participants with type 2 diabetes and 14 healthy controls, recruited from the general community, were studied. Leg hemodynamics were measured before and during aldosterone infusion (0.2 and 5 ng min(-1) [L leg volume](-1)) for 10 minutes into the femoral artery with and without coinfusion of NAC (125 mg kg(-1) hour(-1) followed by 25 mg kg(-1) hour-1). Leg blood flow and arterial blood pressure was measured, and femoral arterial and venous blood samples were collected.Results: Compared with the control group, leg blood flow and vascular conductance decreased during infusion of aldosterone at the high dose in individuals with type 2 diabetes, whereas coinfusion of NAC attenuated this response. Plasma aldosterone increased in both groups during aldosterone infusion and there was no difference between groups at baseline or during the infusions.Conclusion: These results suggests that type 2 diabetes is associated with a vasoconstrictor response to physiological levels of infused aldosterone and that the antioxidant NAC diminishes this response.