Figure 4.

Circulating angiogenic cell (CAC) stimulation of tube formation with a human endothelial vein endothelial cell monolayer. The ability of CACs (stained with CMTMR, red) to stimulate angiogenic tube formation was assessed when cocultured with human umbilical vein endothelial cells on Matrigel. Compared to (a) sham-transduced CACs, (b) endothelial nitric oxide synthase (eNOS)-transduced cells had an improved ability to stimulate tube formation, as measured by several parameters: (c) tube length, (d) the number of nodes, and (e) the rate of CAC association with endothelial cell tubes. *P < 0.05. Bar = 150 µm. EPC, endothelial progenitor cell.