Figure 1.
Effect of Ang-1 on the VEGF-induced angiogenic response of aortic rings made quiescent by a 14-day-long preincubation step in repeated changes of serum-free medium. Quiescent aortic rings were cultured in collagen gel without (A) or with Ang-1 (0.67 μg/ml, B), VEGF (10 ng/ml, C and E) or the Ang-1/VEGF combination (D and F). Note: Ang-1 was unable to induce angiogenesis but potentiated VEGF-induced neovessel sprouting and branching morphogenesis (arrows indicate branch points). The Ang-1 effect on VEGF-treated cultures was dose-dependent (G; Bars = SEM; n = 3; *, P < 0.01. **, P < 0.001 versus VEGF).