Fibrin and Collagen Differentially but Synergistically Regulate Sprout Angiogenesis of Human Dermal Microvascular Endothelial Cells in 3-Dimensional Matrix
Figure 3
Formation of angiogenic sprouts and capillary tube-like structures by HDMEC in fibrin stimulated by VEGF (30 ng/mL) and bFGF (25 ng/mL). (a) In control fibrin gel without addition of angiogenic factors, no significant sprout formation occurred after 48 hr. (b) In the presence of VEGF (30 ng/mL) and bFGF (25 ng/mL), HDMEC formed angiogenic sprouts, and invaded and migrated into the fibrin gel within 48 hr. (c) By 5 days, VEGF and bFGF stimulated HDMEC forming branching capillary tube-like structures in the fibrin gel. (d) Formation of local capillary arcades and networks by HDMEC in fibrin with VEGF and bFGF for 5 days. (e) Formation of wild capillary networks by HDMEC in fibrin with VEGF and bFGF for 5 days. (f) Higher magnification of a typical capillary network illustrates that networks formed as a result of branching and fusion of capillary tubes from neighboring beads. Magnification: (a), (b), and (c) 100x, (d) 40x, (e) 40x, and (f) 200x.
