Fig. 2

Validation of sprout morphology. a Bright field image of vascular sprouts growing out from an EC-coated bead. b Confocal micrograph of a vascular sprout stained for F-actin; a patent lumen is seen on an optical cross-section (inset). c Confocal micrographs of a vascular sprout stained for laminin (red), VE-cadherin (green), and nuclei (DAPI, blue); maximum intensity projection (i), optical cross-section (ii), and optical longitudinal section (iii); 3D configuration of the optical sections is depicted in simplified illustrations (right). d, e Confocal micrographs of human pericyte/EC-derived vascular sprouts stained for endothelial nuclei (Erg-1/2/3, white), pericytes (NG2, red), F-actin (phalloidin, green), and nuclei (DAPI, blue); maximum intensity projection showing a bead with connected sprouts (d), optical longitudinal section of a single sprout (e), showing the vascular lumen (asterisks), EC nuclei (arrowheads), and pericyte nuclei (block arrows). Scale bars, a 200 μm; b, c 10 μm; d 200 μm; e 10 μm