Effect of implanted cell number on vasculogenic performance of EPCs. Matrigel implants containing either 0.5 × 106 (× 1/3) (A,D), 1.5 × 106 (× 1) (B,E,H), or 4.5 × 106 (× 3) (C,F,I) EPCs in the presence of HSVSMCs (4:1 EPCs/HSVSMCs ratio) were evaluated after one week. (A-C) H&E staining of Matrigel implants containing cbEPCs at passage 6 (× 400); (D-F) cbEPCs at passage 12 (× 400); and (G-I) adult EPCs at passage 6 (× 400). (G) Anti–human CD31 immunostained section of adult EPCs at passage 6 seeded at × 3. All images are representative of implants harvested from 4 different animals (scale bar represents 50 μm). (J) Microvessel density was quantified by counting lumenal structures containing red blood cells. Each bar represents the mean microvessel density value determined from 4 separated implants and animals ± SD. *P < .05 compared with × 1/3. †P < .05 compared with × 1.
