In vivo model of vasculogenesis develops VEGF-independent cords. (a) An in vivo model of vasculogenesis in which ADSCs and ECFCs co-implanted into the flank develop blood vessel like structures stained with CD31. The vessels anastamose with the host vessels and have blood cells (erythrocytes; TER119) associated with the vessels beginning on day 4. At later times, however, hemorrhage indicated by TER119 staining not associated with the blood vessels were seen (arrows). (b) Graph of the percent area of CD31 and the percent of vessels associated with erythrocytes (TER119) after 3–6 days of growth in the flank of a mouse. n = 8 per group. * = p < 0.05 vs. day 3. † = p < 0.01 vs. day 4. (c) Images of blood vessels stained with CD31 within the implants after treatment with IgG or ramucirumab (Ram) beginning on day 0 (top) or after 4 days (bottom) of establishment. (d) Graph of the percent area of CD31 after 4 days of treatment with IgG or ramucirumab beginning on day 0 or day 4. n = 10 per treatment group. * = p < 0.0001 vs. all other treatment groups. † = p < 0.01 vs. all other groups.