Branching out requires VEGF

Not all isoforms are created equal. New results from Christiana Ruhrberg, David Shima (Cancer Research UK, London, UK), and colleagues reveal that the stickiness of vascular endothelial growth factor (VEGF) can make all the difference between blood vessels growing larger or finding new territory.VEGF initiates the formation and expansion of the vascular system. VEGF isoforms differ in their ability to bind to the extracellular matrix (ECM), but, in vitro, endothelial cell proliferation is stimulated by VEGF regardless of its ECM-binding ability.

In the new study, Shima's group examined mice engineered to make only single VEGF isoforms. These mice reveal that VEGF isoforms have opposing effects on growing vessel networks. Although all forms stimulated cell growth in vivo, mice that expressed only soluble VEGF had expanded microvessels with fewer branches. In contrast, microvessels...