Vessel-building mast cells

Irradiation instructs mast cells to rebuild blood vessels in oxygen-deprived tissues, according to Heissig and colleagues on page 739. Low-dose irradiation mobilized adult and precursor mast cells, which traveled to the ischemic tissue and produced the vessel-building growth factor VEGF (vascular endothelial growth factor).

Ionizing irradiation has been shown to promote the growth of new blood vessels through the induction of VEGF and inhibition of endothelial cell death. However, the primary source of irradiation-induced VEGF and the precise mechanism that triggers its production were not clear. Mast cells—well-known for their production of histamine in allergic responses—had been found in tissues undergoing angiogenesis. Mast cells are also capable of producing VEGF, but whether these cells play a leading or supporting role in angiogenesis had not been explored.Heissig et al. now show that mast...