Nonocclusive multivessel intracoronary infusion of allogeneic cardiosphere-derived cells early after reperfusion prevents remote zone myocyte loss and improves global left ventricular function in swine with myocardial infarction

Abstract

Intracoronary cardiosphere-derived cells (icCDCs) infused into the infarct-related artery reduce scar volume but do not improve left ventricular (LV) ejection fraction (LVEF). We tested the hypothesis that this reflects the inability of regional delivery to prevent myocyte death or promote myocyte proliferation in viable myocardium remote from the infarct. Swine (n = 23) pretreated with oral cyclosporine (200 mg/day) underwent a 1-h left anterior descending coronary artery (LAD) occlusion, which reduced LVEF from 61.6 α 1.0 to 45.3 α 1.5% 30 min after reperfusion. At that time, animals received global infusion of allogeneic icCDCs (n = 8), regional infusion of icCDCs restricted to the LAD using the stop-flow technique (n = 8), or vehicle (n = 7). After 1 mo, global icCDCs increased LVEF from 44.8 α 1.9 to 60.8 α 3.8% (P < 0.05) with no significant change after LAD stop-flow icCDCs (44.8 α 3.6 to 50.9 α 3.1%) or vehicle (46.5 α 2.5 to 47.7 α 2.6%). In contrast, global icCDCs did not alter infarct volume (%LV mass) assessed at 2 days (11.2 α 2.3 vs. 12.6 α 2.3%), whereas it was reduced after LAD stop-flow icCDCs (7.1 α 1.1%, P < 0.05). Histopathological analysis of remote myocardium after global icCDCs demonstrated a significant increase in myocyte proliferation (147 α 32 vs. 14 α 10 nuclei/106 myocytes, P < 0.05) and a reduction in myocyte apoptosis (15 α 9 vs. 46 α 10 nuclei/106 myocytes, P < 0.05) that increased myocyte nuclear density (1,264 α 39 vs. 1,157 α 33 nuclei/mm2, P < 0.05) and decreased myocyte diameter (13.2 α 0.2 vs. 14.5 α 0.3 μm, P < 0.05) compared with vehicle-treated controls. In contrast, remote zone changes after regional LAD icCDCs were no different from vehicle. These data indicate that changes in global LVEF after icCDCs are dependent upon preventing myocyte loss and hypertrophy in myocardium remote from the infarct. These arise from stimulating myocyte proliferation and reducing myocyte apoptosis indicating the importance of directing cell therapy to viable remote regions.