REGENT is a multicenter, randomized trial for comparison of intracoronary infusion of bone marrow-derived unselected mononuclear cells (MNC) and selected CD34+CXCR4+ cells in 200 patients with acute myocardial infarction and reduced LVEF ≤ 40%.
Primary end-point was change of LV ejection fraction (LVEF) and volumes measured by MRI before and 6 months after the procedure.
In patients receiving both selected and unselected bone marrow cells, LVEF increased significantly in comparison to baseline values by 3%. This increase, however, was not significantly higher in comparison to the control group. The changes of left ventricular volumes were also comparable in all groups. Significant increase of LVEF was observed in patients treated with either type of bone marrow cells who had baseline LVEF < median. Baseline LVEF was an independent predictor of significant increase of LVEF. At 6 months clinical follow-up, major cardiovascular event rate was low, and no different between the groups.
In conclusion, treatment with intracoronary infusion of BMC did not lead to significant improvement of LVEF and LV volumes in comparison to control group, however there was a trend towards significant improvement of LVEF in patients with severely depressed baseline LVEF receiving either MNC or CD34+CXCR4+ bone marrow cells. Intracoronary infusion of unselected and selected BMC proved to be safe and feasible.
REGENT is the second-largest trial using bone marrow-derived cells in patients with acute MI and the first large trial for head-to-head comparison of selected and unselected cells. Population of CD34+CXCR4+ cells is enriched in cardiac committed progenitor cells, but so far it has not been used in a clinical trial. The results suggest that in patients with severely depressed LVEF administration of a relatively small number of CD34+CXCR4+ cells can have the same effect as an infusion of a larger number of MNC. Therefore, this cell population deserves further studies.