Vascular endothelial growth factor, or VEGF, is a substance made by cells in the body that stimulates new blood vessel growth.
It also increases leakiness, or permeability, of blood vessels. Prior to being born, when we are developing in the womb, VEGF is important to blood vessel growth.
VEGF is still believed to have important roles after we are born; however, in the eye, at least one type of VEGF causes abnormal blood vessel growth.
VEGF is believed to be triggered or stimulated by various factors, such as poor oxygenation, inflammation, and cancer.
The scientific recognition of VEGF as a major factor in the growth of new blood vessels associated with macular degeneration has led to the major breakthroughs in treatment with anti-VEGF therapy, such as Lucentis and Avastin.
VEGF works by binding to receptors on certain cells of the body and then triggering the receptors to initiate an action.
In the case of wet macular degeneration, the triggered action is the growth of new blood vessels, as well as increased permeability (leakiness) of vessels and the signaling of other cells to come to the area.