The timing of intra-coronary infusion of G-CSF mobilized peripheral blood stem cells influences cardiac function and in-stent restenosis in patients with myocardial infarction.

We hypothesized that delaying the timing of intra-coronary infusion of G-CSF mobilized stem cell until at least 4 weeks after coronary stenting should avoid the stimulation of vascular smooth muscle cells during the early active cellular proliferative phase, thus decreases in-stent restenosis while preserving the beneficial effect of stem cell therapy on cardiac function in patients with myocardial infarction (MI). 25 patients with ST-elevation myocardial infarction (STEMI) treated with stenting were enrolled in this pilot study. The ages of MI at the time of cell treatment were from 1 month to 59 months. At 6 months follow-up, the left ventricular ejection fraction (LVEF) increased from 32% to 37.7% and the stress thallium perfusion defect decreased from 31.4% to 28.1%. Cell treatment-related complications such as arrhythmias were not observed. 9 patients who underwent cell treatment less than 3 months after coronary stenting were evaluated for in-stent restenosis; it was found in only 1 patient. This pilot study shows that delayed more than 4 weeks after coronary stenting but less than 3 months after MI, intra-coronary infusion of G-CSF mobilized PBSCs may improve cardiac function without triggering in-stent restenosis.