Background: Recent studies suggest that endothelial progenitor cells (EPC) from bone marrow or peripheral blood improve myocardial function in experimental myocardial infarction (MI). Since applications for cell therapy are limited by the number of available cells, expansion of EPC may facilitate its therapeutic use in ischemic disease. The aim of this study was to expand late outgrowth EPC from peripheral blood from patients with acute myocardial infarction, characterize them and investigate their therapeutic effect in experimental MI.
Methods and Results: Venous blood samples were obtained from patients with acute MI (n=51), stable angina (sAP, n=57) and healthy controls (H,n=47). CD34+ cells were isolated using immunomagnetic beads (Miltenyi Biotec). CD34+ cells cultured on fibronectin in endothelial cell medium formed colonies after 1–2 weeks and were further expanded for up to 3 months to generate late outgrowth EPC (eEPC). Expansion was observed up to 2.9x10′9 (MI), 11x10′9 (sAP) and 7x10′9 cells (H) with a mean culture duration of 61 days. Expanded cells showed an endothelial morphology and expressed endothelial surface markers (CD31, VEGF-R2, CD105). Intramyocardial transplantion of 1x10′6 eEPC in experimental myocardial infarction in athymic nude rats revealed improvement in echocardiographic ejection fraction after 2 weeks. This was associated with enhanced vessel density after 1 week and increased mRNA expression of HGF. No differences in infarct size were observed. Similarly in a chronic model of myocardial infarction (eEPC transplantation 1 week after MI) myocardial function significantly improved after 5 weeks in comparison to the control group.
Conclusion: Expansion of eEPC from circulating CD34+ cells in patients with coronary artery disease is feasible and improves myocardial function after local transplantation in acute and chronic myocardial infarction. The large number of generated eEPC may prove benefical for therapeutic use and this advantage may prevail time-consuming expansion procedures.
Circulating exosomal miR-144-3p inhibits the mobilization of endothelial progenitor cells post myocardial infarction via regulating the MMP9 pathway
