Fig. 3

Fluorescent imaging of network region-dependent integration of human MSCs in the aortic ring assay after 24 and 72 hours. Prestained (CellTrackerGreen™) FTM HUCPVCs and FBS containing media-expanded BMSCs added to developing aortic ring endothelial tube networks. Fluorescence microscopy images taken 24 hours after establishing MSC cocultures. FTM 1 and FTM 2 migrate through ECM and home to peripheral developing endothelial networks (a, b). Higher magnification images display elongated morphologies of FTM HUCPVCs while in close contact with endothelial networks (d, e). Fewer BMSCs process ECM and home to endothelial networks with no observable preference to peripheral developing networks (c). BMSCs display spherical cell morphologies (f). High-magnification fluorescence microscopy images of prestained MSCs in rat aortic ring assay following 72 hours of coculture (g, h, i). FTM 1 and FTM 2 display elongated morphologies while displaying endothelial coverage through direct cell-to-cell interactions with endothelial cells (solid white arrows) both in network nodes and tubules (g, h). BMSCs maintain spherical cell morphologies clustered in endothelial network nodes (i). Broken arrow shows direction of endothelial network growth from aortic ring tissue. Low-magnification images, scale bar = 1000 μm; high-magnification images, scale bar = 400 μm. BMSC bone marrow stromal cell, FTM first trimester (Color figure online)