Intracoronary infusion of bone marrow-derived selected CD34+CXCR4+ cells and non-selected mononuclear cells in patients with acute STEMI and reduced left ventricular ejection fraction: results of randomized, multicentre Myocardial Regeneration by Intracoronary Infusion of Selected Population of Stem Cells in Acute Myocardial Infarction (REGENT) Trial.

AIMS: Comparison of intracoronary infusion of bone marrow (BM)-derived unselected mononuclear cells (UNSEL) and selected CD34(+)CXCR4(+) cells (SEL) in patients with acute myocardial infarction (AMI) and reduced <40% left ventricular ejection fraction (LVEF).

METHODS AND RESULTS: Two hundred patients were randomized to intracoronary infusion of UNSEL (n = 80) or SEL (n = 80) BM cells or to the control (CTRL) group without BM cell treatment. Primary endpoint: change of LVEF and volumes measured by magnetic resonance imaging before and 6 months after the procedure. After 6 months, LVEF increased by 3% (P = 0.01) in patients treated with UNSEL, 3% in patients receiving SEL (P = 0.04) and remained unchanged in CTRL group (P = 0.73). There were no significant differences in absolute changes of LVEF between the groups. Absolute changes of left ventricular end-systolic volume and left ventricular end-diastolic volume were not significantly different in all groups. Significant increase of LVEF was observed only in patients treated with BM cells who had baseline LVEF < median (37%). Baseline LVEF < median and time from the onset of symptoms to primary percutaneous coronary intervention > or = median were predictors of LVEF improvement in patients receiving BM cells. There were no differences in major cardiovascular event (death, re-infarction, stroke, target vessel revascularization) between groups.

CONCLUSION: In patients with AMI and impaired LVEF, treatment with BM cells does not lead to a significant improvement of LVEF or volumes. There was however a trend in favour of cell therapy in patients with most severely impaired LVEF and longer delay between the symptoms and revascularization.