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. 2002 Oct 15;16(20):2684–2698. doi: 10.1101/gad.242002

Figure 2.

Figure 2

The balanced expression of heparin-binding VEGF-A versus VEGF120 controls microvessel branching and vessel caliber. (A) Schematic representation of hindbrain vascularization between 10.0 (1) and 10.5 (4) dpc; between 9.5 and 10.0 dpc, the perineural vascular plexus in the pial membrane begins to extend sprouts into the neural tube (1), which grow perpendicularly toward the ventricular zone (2), where they branch out to form the subventricular vascular plexus (3,4). (B,C) Microvessel appearance on the pial and ventricular sides of a flat-mounted 12.5-dpc hindbrain; the midline region is indicated with an asterisk; the pial side of the hindbrain with P, the ventricular side with V. (D–F) Visualization of vascular networks in representative 500-μm2 areas of the 13.5-dpc midbrain of wt/wt (D), wt/120 (E), and 120/120 (F) littermates; blood vessels were visualized with a Tie2LacZ reporter. (G) Number of microvessel branch points per 500-μm2 area in the subventricular zone of the embryonic central nervous system in wt/wt (black), wt/120 (red), and 120/120 (green) littermates; n = 3 for each specimen; 10.75-dpc hindbrain (1); 11.25-dpc hindbrain (2); 13.5-dpc hindbrain (3); 11.25 spinal cord (4); and 13.5-dpc midbrain (5). (H,I) Ultrastructure of microvessels in wt/wt (H) and 120/120 (I) hindbrains of littermates at 10.75 dpc, visualized by transmission electron microscopy (TEM); endothelial nuclei are indicated with red stars. (J) Number of endothelial cell nuclei per capillary cross section in the hindbrain in wt/wt (n = 96) and 120/120 (n = 106) littermates at 10.75 dpc (P ≤ 0.0001, Mann-Whitney test). (K,L) Endothelial cell proliferation in hindbrain vessel cross sections of wt/wt (K) and 120/120 (L) littermates at 11.25 dpc; PECAM-positive vessels are shown in green, BrdU-positive endothelial nuclei (white stars) in red. (M) HUVEC proliferation assay; VEGF-A (VEGF121 or VEGF165) concentration: 0.5 ng/mL (1) , 2 ng/mL (2) , 10 ng/mL (3) , 20 ng/mL (4); and basic fibroblast growth factor concentration 3 ng/mL (5). Bars: B,C, 500 μm; D–F, 100 μm; K,L, 5 μm. Magnification: H,I, 5500×.