VEGF-A Induces Angiogenesis, Arteriogenesis, Lymphangiogenesis, and Vascular Malformations

Abstract

The mature vasculature develops initially from thetwin processes of vasculogenesis (de novo formation ofblood vessels from primitive precursors) and angiogenesis (formation of new blood vessels from preexisting vessels) (Folkman and D'Amore 1996; Beck and D'Amore1997; Folkman 1997; Hanahan 1997; Risau 1997; Galeand Yancopoulos 1999). The resulting blood vessels thatcome to supply normal adult tissues are distributed at regular and closely spaced intervals and are organized into ahierarchy of elastic and muscular arteries, arterioles, capillaries, post-capillary venules, and small and large veins.Each of these vessel types has a characteristic size andstructure that allow it to perform specialized functions.Thus, muscular arteries and arterioles regulate pressure;capillaries are the major site of molecular exchange; andvenules and small veins are the primary vascular segments responsive to inflammation, whether humoral(plasma extravasation initiated by histamine, VEGF-A,etc.) or cellular (inflammatory cell extravasation)...