Context: Primary aldosteronism (PA) is associated with a higher incidence of cardiovascular events, probably through mineralocorticoid receptor (MR)-dependent endothelial cell dysfunction, in comparison with essential hypertension (EH).
Objective: Our objective was to investigate the number and function of endothelial progenitor cells (EPC) in PA and the relationship with arterial stiffness and disease progression.
Design and setting: We conducted a prospective study of the change of EPC number and outcome of PA patients after treatment at a tertiary medical center.
Primary outcomes: Changes in arterial stiffness and EPC number after treatment and the curability of hypertension were assessed.
Patients: A total of 113 PA patients (87 patients diagnosed with aldosterone-producing adenoma, 26 with idiopathic hyperaldosteronism) and 55 patients with EH participated.
Results: PA patients had higher arterial stiffness than EH patients (P = 0.006), with a lower numbers of circulating EPC and endothelial colony-forming units (P < 0.05). The differences were ameliorated at 6 months after unilateral adrenalectomy or treatment with spironolactone. Expression of MR was identified in the EPC. The number of circulating EPC was inversely correlated with the plasma aldosterone concentration (P = 0.021), arterial stiffness (P = 0.029) and serum high-sensitivity C-reactive protein (P = 0.03). High-dose aldosterone (10(-5) and 10(-6) m) attenuated EPC proliferation and angiogenesis in vitro. Among the 45 patients who underwent unilateral adrenalectomy, 32 (71%) were cured of hypertension. The preoperative number of EPC [log(EPC number percent) >-3.6] predicted the curability of hypertension after adrenalectomy (P = 0.003).
Conclusions: The relative deficiency of EPC in PA patients may contribute to aldosterone vasculopathy, which can be reversed by adrenalectomy and spironolactone. High aldosterone levels attenuated EPC proliferation and angiogenesis. Circulating EPC number may be a valuable biomarker to identify PA patients with a high incidence of arterial stiffness and to predict postoperative residual hypertension of aldosterone-producing adenoma.