The angiogenic response of the aorta to injury and inflammatory cytokines requires macrophages.

The purpose of this study was to define early events during the angiogenic response of the aortic wall to injury. Rat aortic rings produced neovessels in collagen culture but lost this capacity over time. These quiescent rings responded to vascular endothelial growth factor but not to a mixture of macrophage-stimulatory cytokines and chemokines that was angiogenically active on fresh rings.