Angiogenesis: the role of the microenvironment in flipping the switch

The initiating factors in angiogenesis during development and disease are o ften microenvironmental changes, which induce signaling to the vasculature from affected tissues. Among these, lowered oxygen pressure, hypoxia, is on e of the most potent inducers/initiators of an angiogenic response. Signifi cant evidence indicates that hypoxia acts as a morphogen during vasculariza tion - inducing and shaping the recruitment and formation of new vascular b eds through critical transcriptional control pathways. Recent advances indi cate that extensive interactions occur between developing blood vessels, th e tissues that they vascularize, and the interstitial environment to contro l and shape the establishment of new capillary beds. Identification of the processes that control the hypoxic response intracellularly has allowed an increasingly sophisticated understanding of angiogenesis as a process that is very closely tied to the microenvironment that it occurs in. Further und erstanding of these processes may present powerful therapeutic opportunitie s for disease intervention.