CD34+ enriched cell products intended for autologous transendocardial CD34+ cell transplantation release significant amounts of angiopoietin-1.

OBJECTIVES: Cell-based therapy has emerged as a promising strategy for the treatment of patients with heart failure. Increasing evidence supports the hypothesis that paracrine mechanisms mediated by soluble factors released by the cells play a predominate role in reparative processes. The aim of our study was to analyze which cytokines are released by CD34+ enriched cell products intended for autologous transendocardial CD34+ cell transplantation in patients with cardiomyopathy. MATERIAL AND METHODS: The peripheral blood CD34+ cells from 12 patients were mobilized with granulocyte colony-stimulating factor, collected via apheresis and enriched by immunoselection. RESULTS: In CD34+ enriched cell population, hematopoietic, but not mesenchymal or endothelial, progenitors were detected. Except for angiopoietin-1, other measured cytokines (FGF1, FGF2, VEGF, PDGF, IL-6, HGH, SDF-1α/CXCL12, NRG1) were not released by CD34+ cells. The average concentration of angiopoietin-1 released by 5×106 CD34+ cells grown in neutral DMEM medium was 213.6±130.0pg/mL (range: 74-448pg/mL). Angiopoietin-1 secretion correlated well with CD34+ cell's capacity for generating colonies derived from hematopoietic progenitors (Pearson's correlation=0.964; P<0.001). CONCLUSION: Our study presents angiopoietin-1 as an interesting candidate and suggests future studies to explore how its release by CD34+ cells might impact the success of autologous CD34+ cell transplantation.