| Angiogenesis is a regulated process involving the proliferation, migration, and remodeling of
different cell types particularly mature endothelial cells and recently discovered progenitor cells,
named as endothelial progenitor cells (EPCs). Up to now, many attempts have been made to
understand the dynamic balance of pro- and anti-angiogenic factors on EPCs on different milieu.
It has been accepted that Ang-1, -2 and Tie-1, -2 signaling play a key role on angiogenesis
pathways in endothelial lineage cells. In the current experiment, the angiogenic/angiomodulatory
potency of Ang-1 and -2 was investigated on isolated EPCs. Freshly isolated EPCs
were exposed to different concentrations of Ang-1 and -2 (25 and 50 ng/ml) over a course of 7
and 14 days. Corroborating to our results, a superior effect of Ang-1 on angiogenic properties,
including an increased concentration of vascular endothelial growth factor, in vitro
tubulogenesis, EPC migratory, Tie-2 expression and clonogenicity, was determined. A large
amount of positive mature endothelium markers was achieved in EPCs being-exposed to Ang-1
peptide. Nonetheless, the number of CD133 positive cells increased in the presence of Ang-2.
Collectively, we conclude that Ang-1 potentially induces functional and mature vascular-like
behavior in EPCs more than Ang-2. |