Endothelial cell tubulogenesis in the presence of MSC-conditioned media measured by (A) the number of branch points per field of view and (B) total tubule length. Significance is denoted by alphabetical letterings; groups with no significance are linked by the same letters, while groups with significance do not share the same letters (n=4). Representative images of endothelial cell tubulogenesis on Matrigel in the presence of MSC-conditioned medium from (C) S1, (D) S2, and (E) EBM-2. Scale bar represents 500 μm; images captured using a 4X objective. Abbreviations: EGM-2, endothelial cell growth media, positive control; GF-Def EGM-2, growth factor deficient EGM-2, experimental control; EBM-2, endothelial basal media, negative control. S1, Spheroid 1; S2, Spheroid 2; A1, Adherent 1; A2, Adherent 2.