VEGF secretion from cultured EPC in vitro incubated with basal medium (BM) or differentiation medium (DM). Results are presented on a logarithmic scale. There is a significant increase in VEGF production upon differentiation in both EV-EPC and GBP-1-EPC. There is no significant difference between EV-EPC and GBP-1-EPC when basal medium is used. After incubation with differentiation medium, however, GBP-1-EPC secrete significantly higher levels of VEGF into the supernatant medium compared to EV-EPC. (p<0.05).