5987Neovascularization potential of exosomes derived from blood outgrowth endothelial cells in ischemic cardiomyopathy

Introduction: Blood outgrowth endothelial cells (BOECs) mediate therapeutic neovascularization in experimental models. We hypothesized that BOECs promote angiogenesis via secretion of exosomes. Methods: BOECs were isolated from the peripheral blood of patients with severe ischemic heart disease and were exposed to hypoxia (1% O2) or normoxia for 12h. Exosomes were isolated from the medium by differential ultracentrifugation. Size and the number of exosomes were determined by nano tracking analysis (NTA) and immunoblot analysis of the surface markers of exosomes. Matrigel 2D-tube formation assay was performed to explore the angiogenic potential of HUVECs in the presence or absence of BOEC-derived exosomes. qPCR analysis was performed to investigate transcript levels of angiogenic factors both in BOECs and in BOEC-derived exosomes. Proteomic analysis was performed to investigate angiogenic factors in BOECs from patients and controls and validated using ELISA. We measured the expression of miRNAs miR-210, miR-221, miR-126, and miR-21, with an established role in angiogenesis during normoxia and hypoxia. Finally, we compared in vivo angiogenesis of BOECs and BOEC-derived exosomes using a wound healing model in nude mice.