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Fig. 5. Modulation of 3D sprouting angiogenesis (A) and endothelial alignment on
Matrigel (B) by EphB4-Fc and ephrinB2-Fc. (A) Quantitative analysis of the
cumulative sprout length (CSL, quantitated after 48 hours) originating from 10
collagen gel embedded HUVEC spheroids (one out of three independent
experiments with similar results). Representatives of each experimental group
are shown below the bar graph (bar, 100 µm). EphB4-Fc (1 µg/ml) as well
as VEGF (50 ng/ml) induce capillary-like sprouting. By contrast, ephrinB2-Fc
(1 µg/ml) inhibits baseline sprouting as well as VEGF-induced sprouting
angiogenesis. (B) Quantitative cellular alignment analysis of ECs grown on
Matrigel. HUVECs were grown on Matrigel for 24 hours after which the
circumferential length of tube-like structures was quantitated by automated
image analysis. EphrinB2-Fc significantly inhibits alignment of HUVECs.
**P<0.01; ***P<0.01 (compared with baseline control);
P<0.01 (compared with VEGF induction).