Background: Glucagon-like peptide-1(GLP-1), released from enteroendocrine cells of the intestine, exerted cardiovascular protective effect. Circulating endothelial progenitor cells (EPCs) play an important role in maintaining endothelial integrity regulating neovascularization and reendothelialization after endothelial injury. Vascular endothelial growth factor (VEGF) is an important cytokine in the process of EPCs vascular differentiation and proliferation.
Material/Methods: This study was designed to investigate the association between VEGF changes and the proliferation/differentiation function of EPCs in the presence of GLP-1.
Results: We demonstrated that GLP-1 markedly enhanced the EPCs proliferation and expression of EC-specific markers, and simultaneously upregulated VEGF secretion in EPCs. Exogenous VEGF augmented EPCs proliferation/differentiation abilities in a dose-dependent manner. However, all of the beneficial effects of GLP-1were suppressed by anti-VEGFmAb or the KDR-specific tyrosine kinase inhibitor SU1498.
Conclusions: These findings suggest that GLP-1 improves VEGF generation, which contributed to improvement of EPCs biological function, partly by tyrosine kinase KDR. VEGF is a necessary intermediate, mediating the effects of GLP-1 on EPCs. These changes offer a novel explanation that upregulation EPCs bioactivities may be one of the mechanisms of GLP-1 cardiovascular protective effect.

Keywords: Up-Regulation - drug effects, Vascular Endothelial Growth Factor A - pharmacology, Stem Cells - enzymology, RNA, Messenger - metabolism, Nitric Oxide Synthase Type III - metabolism, Glucagon-Like Peptide 1 - pharmacology, Endothelial Cells - cytology, Cell Shape - drug effects, Cell Proliferation - drug effects, Cell Differentiation - drug effects, Antigens, CD - metabolism, Vascular Endothelial Growth Factor Receptor-1 - metabolism, Vascular Endothelial Growth Factor Receptor-2 - metabolism