ANGIOGENESIS
By
Alida Kinney and Julie Ho
Vertebrate Embryology
Brown University
A
Angiogenesis is essential to the body. Not only does it play an important role in the early development of the embryo, but also is a process that continues throughout life. We will look at specifically the process of angiogenesis in embryonic development and also address some of the problems that arise from abnormal angiogenesis.
BAngiogenesis is defined as the branching and extension of existing capillaries, whose walls consist of just one layer of so-called endothelial cells. 1 In embryonic development, angiogenesis contributes to the formation of new blood vessels that contribute nutrients and oxygen, and remove wastes to and from the growing fetus.
After birth, angiogenesis helps in repairing injured tissues and wound healing. In mature women, this process also aids in lining the uterus each month during the menstrual cycle. When fertilization occurs, angiogenesis plays a further role in the development of the placenta. Most studies indicate that angiogenesis is the basis for neovascularization in the adult 2 due to the numerous ways in which angiogenesis contributes to the development and maintenance of the body as a whole.
The process of angiogenesis is maintained within the body at an equilibrium and is governed by growth factors and inhibitors. When this balance is disrupted, blood vessels form at inappropriate times and places. Excessive vessel formation results in tumors, cancerous growth, and other abnormalities, while insufficient vessel formation contributes to heart diseases, ulcers, etc. Consequences of both cases can be detrimental to the victim, demonstrating that the fine balance between growth factors and inhibitors in angiogenesis must be maintained for the continuation of life.
B