Vasculogenesis and Angiogenesis

Vasculogenesis, angiogenesis, and arteriogenesis are terms used to describe the formation of blood vessels. Embryonic neovascularization by vasculogenesis refers to the formation of primitive blood vessels inside the embryo and its surrounding membranes and involves the in situ differentiation of mesoderm-derived angioblasts, which aggregate and form de novo blood vessels. Vascularization of the brain occurs primarily through angiogenesis. Angiogenesis involves the formation of new blood vessels via sprouting or splitting from pre-existing vessels and occurs both pre- and postnatally. Arteriogenesis refers to the enlargement of pre-existing collateral arterioles to form larger arteries. Specific angiogenic factor signaling systems choreograph each step of blood vessel formation. Vasculogenesis and angiogenesis are not exclusive processes but instead constitute complementary mechanisms for postnatal neovascularization.