Primary aldosteronism (PA) and endothelial progenitor cell (EPC) bioavailability

OBJECTIVE: Patients with primary aldosteronism (PA) experience more cardiovascular events than patients with essential hypertension matched for risk factor profile. Endothelial progenitor cells (EPC) represent a bone marrow-derived cell population implicated in vascular healing whose number correlates to the cardiovascular risk factor profile. Aldosterone has been reported to decrease EPC proliferation in rats. DESIGN AND PATIENTS: We assessed (i) the growth characteristics of EPC from six PA patients and six matched normotensive controls; (ii) the growth characteristics of EPC treated with increasing doses of aldosterone. MEASUREMENTS: Senescence and cell-cycle analysis of EPC from PA patients and normotensive controls and of aldosterone-treated EPC from healthy volunteers. RESULTS: No difference was found in the senescence rate between EPC from PA patients (72.4% senescent cells) and controls (70.7%, P > 0.05). No difference was also found in the cell-cycle distribution determined by FACS (controls: 75.2% cells in G0/G1 phase; PA: 73.5%, P > 0.05). Incubation of EPC with aldosterone did not modify their senescence rate (controls: 72.4% senescent cells; aldosterone 10 nmol/l: 70.9%; aldosterone 100 nmol/l 71.6%, P > 0.05 for all comparisons) and cell-cycle distribution (controls: 73.3% cells in G0/G1 phase; aldosterone 10 nmol/l: 74.9%; aldosterone 100 nmol/l: 75.4%, P > 0.05 for all comparisons). No expression of the mineralocorticoid receptor (MR) transcript was found in EPC by RT-PCR analysis. CONCLUSIONS: High aldosterone levels, both in PA patients and in vitro, exert no direct or indirect effect on EPC growth characteristics.