Reduction in infarct size, but no functional improvement after bone marrow cell administration in a porcine model of reperfused myocardial infarction

Abstract

Stem cell therapy after myocardial infarction (MI) has been studied in models of permanent coronary occlusion. We studied the effect of intracoronary administration of unselected bone marrow (BM) and mononuclear cells (MNC) in a porcine model of reperfused MI. In 34 swine, the left circumflex coronary artery was balloon-occluded for 2 h followed by reperfusion. Ten swine without MI served as controls. All swine underwent magnetic resonance imaging (MRI) 1 week post-MI. The next day, 10 of the 30 surviving MI swine received BM, 10 other MI swine received MNC, and the remaining MI swine received medium intracoronary. Four weeks later, all swine underwent a follow-up MRI. One week after MI, end-diastolic volume (92+/-16 mL) and left ventricular (LV) weight (78+/-12 g) were greater, whereas ejection fraction (40+/-8%) was lower than in controls (69+/-11 mL, 62+/-13 g, and 53+/-6%). Injection of BM or MNC had no effect on the MI-induced changes in global or regional LV-function. However, there was a significant reduction in infarct size 4 weeks after MNC injection (-6+/-3%) compared with the medium (-3+/-5%). Intracoronary injection of BM or MNC in swine does not improve regional or global LV-function 4 weeks after injection. However, a reduction in infarct-size was noted after MNC injection.