Angiogenesis, VEGF and AMD

Genentech is a leader in research and product development in the area of angiogenesis, the process by which new blood vessels are formed. In 1989 Napoleone Ferrara, M.D., and a team of scientists at Genentech conducted seminal work in the field, which resulted in the identification and cloning of a gene for a protein called Vascular Endothelial Growth Factor (VEGF), now known as VEGF-A. The VEGF protein plays a critical role in physiological and pathological angiogenesis, and serves as one of the contributors to physiological or pathological conditions that can stimulate the formation of new blood vessels. The process of angiogenesis is normally regulated throughout development and adult life, and the uncontrolled growth of new blood vessels is an important contributor to a number of pathologic conditions, including wet age-related macular degeneration (AMD).

Angiogenesis begins very early in embryonic development and is essential for the differentiation and migration of cells that give rise to blood vessels. As the embryo develops, new blood vessel formation is required to support the growth of the major organs. This is because cells in the body depend on blood vessels as a source of oxygen, nutrients and growth factors, all of which are carried in the blood. The mechanisms by which cells take in oxygen and nutrients and give off carbon dioxide and waste products function only over a very short distance, the width of just a few cells. At larger distances, cells begin to starve and suffocate and may accumulate toxic levels of waste products. Thus, in a developing embryo, new blood vessels are continually forming in order to ensure an adequate supply of oxygen and nutrients to the growing organs. Angiogenesis does not occur in normal adult tissue.

In the 1990s Genentech scientists and their collaborators evaluated the association between VEGF levels and ocular diseases known to involve the growth of new blood vessels from the retina (ocular angiogenic diseases).

Healthy Macula

Macula with Wet AMD

Image Source: Medical illustration courtesy of Macular Degeneration Research, a program of the American Health Assistance Foundation (

In wet AMD, VEGF-A is believed to play a significant role in the formation of blood vessels that grow abnormally and leak beneath the macula. These blood vessels are fragile and can bleed and potentially cause distortion of the retina leading to deterioration of central vision.