Capillarogenesis on Matrigel. MMECs of a representative patient were seeded on Matrigel in serum-free medium (SFM). After a 12-hour incubation, their 3-D organization in response to the indicated agents was examined through a Leitz Labiovert inverted phase-contrast light microscope (Leitz, Wetzlar, Germany), using a 20×/0.50 numeric aperture objective. Images were processed and analyzed using a Leica QWin computed image analysis software (Leica Imaging Systems, Cambridge, United Kingdom). The areas are shaded, the vascular branching points are red.