FIG. 4.

Time course of vascular morphogenesis. (A) Four hours postseeding (“day 0”), the culture contained small numbers of both αSMA+ cells (0.5%; red) and CD31+ cells (0.02%; green; higher magnification shown in inset). Over the course of several days, a multicellular CD31+ vessel emerged and elongated. αSMA+ cells increased in number over time, and began to cluster around the vessels in the second week. (B) DAPI counterstains (blue) of the same view fields illustrate the increasingly dense clustering of cells around the vessel over time. (C) Cross-sectional views of the vessels depict three-dimensional growth over time, accompanied by the migration of cells on top of the vessel. Scale bars=200 μm (A, B) and 5 μm (C). Color images available online at www.liebertonline.com/tea