Improvement in endothelial progenitor cells from peripheral blood by ramipril therapy in patients with stable coronary artery disease

Aims: The aim of this study is to investigate whether angiotensin-converting enzyme inhibitor (ACEI) therapy with ramipril could augment circulating endothelial progenitor cells (EPCs) with enhanced functional activity in patients with stable coronary artery diseases. Methods and results: 20 patients with angiographically documented stable coronary artery disease ( CAD) were prospectively treated with 5 mg of ramipril per day for 4 weeks. Before and weekly after the initiation of ramipril therapy, EPCs were isolated from peripheral blood and counted. Ramipril treatment of patients with stable CAD was associated with an approximately 1.5-fold increase in the number of circulating EPCs by 1 week after initiation of treatment; this was followed by sustained increased levels to approximately 2.5-fold throughout the 4-week study period. In addition, ramipril treatmen was associated with increases in the functional activity of EPCs, as assessed by their proliferation, migration, adhesion and in vitro vasculogenesis capacity. Conclusion: The results of the present study define a novel mechanism of action of ACEI treatment in patients with stable CAD: the augmentation of circulating EPCs with enhanced functional activity. Given the well-established role of EPCs of participating in repair after ischemic injury, stimulation of EPCs by ACEI may contribute to the clinical benefit of ACEI therapy in patients with CAD.