FIG. 3.

Endothelial cell network formation varies with clonal hMSC lines HS-5 and HS-27a in bi-cell patches. An antibody against rabbit CD31 marked endothelial cells (brown) throughout 8 days of in vitro culture for two-cell patches with HUVECs and either HS-5 or HS-27a hMSCs (A). Endothelial cell networks were more abundant in H:HS-27a patches compared to H:HS-5 patches at all time points. Further, the number of vessel-like structures per mm² decreased with time in culture (B; *p < 0.05 vs. H:HS-5 on same day; ^#p < 0.05 vs. previous time point with same cell composition). Compressed z-stacks taken with confocal microscopy show GFP-positive clonal hMSCs (green), hCD31-positive HUVECs (red), and blue nuclei (C). HUVECs and HS-27a hMSCs are closely apposed in day 8 tri-cell patches (bottom) but HUVECs and HS-5 hMSCs are somewhat isolated from each other (top). Scale bars apply to all panels of (A) or (C).