BACKGROUND The results of stem cell therapy trials in myocardial infarction using granulocyte colony-stimulating factor (G-CSF) are inconsistent among trials, and the long-term outcome of G-CSF-based stem cell therapy remains unknown. We reported 2 years of follow-up results of 2 different strategies of G-CSF-based stem cell therapy.

METHODS AND RESULTS We compared outcomes of intracoronary infusion of the mobilized peripheral blood stem cells (PBSCs) with G-CSF, mobilization alone with G-CSF, and the control PCI alone in patients with myocardial infarction. At 2 years of follow-up evaluation, cell infusion improved left ventricular systolic function and remodeling compared to baseline, but G-CSF alone did not. Cell infusion group showed better improvements of left ventricular ejection fraction (+6.2% +/- 3.6% vs -4.3% +/- 10.1%, P = .004) and end-systolic volume (-15.7 +/- 13.0 vs +0.3 +/- 16.7 mL, P = .075) compared to G-CSF alone at 6 months of follow-up, and these trends were maintained till 2 years of follow-up (P = .094 and .046, respectively). Improvements in cell infusion group are not significantly better than that of control group because of small sample size. Patients who received G-CSF administration showed a tendency of modest increase of binary restenosis (50% vs 30%, P > .05) and a greater late loss of minimal luminal diameter (P > .05) at 6 months of follow-up, compared to the control group.

CONCLUSIONS Till 2 years follow-up, intracoronary cell infusion with mobilized PBSCs by G-CSF is better than G-CSF alone but not significantly better than control. Efficacy and safety of intracoronary infusion of mobilized PBSCs by G-CSF should be evaluated in a large randomized controlled trial.