Aaron Welch
Professor Bowman
BIOL 1014
18 April, 2011
Angiogenesis abnormalities
What is angiogenesis?   Angiogenesis is a very important natural process in the human body that can be quite beneficial but also drastically fatal. It is the growth of new capillary blood vessels in the body and is used for healing and reproduction. The body controls the angiogenesis process and tries to create a balanced cycle of growth and inhibitory factors. Without the balance between the two factors many times the process can become abnormal and blood vessel growth will be either excessive or insufficient. Over 1 billion people worldwide are affected by angiogenesis type disorders.
We start with the actual process of angiogenesis which occurs in many steps. The first couple steps start when the diseased or injured tissue releases angiogenic growth proteins. Growth factors then bind to receptors on nearby blood vessels and the endothelial cells become activated. The cells machinery begins manufacturing new molecules like enzymes that dissolve tiny holes in the sheathing like covering. Endothelial cells begin dividing and migrating out through dissolved holes of the existing vessel and adhesion molecules serves as hooks to pull in the new blood vessel. The vessel then elongates and sprouting endothelial cells roll to form a blood vessel tube. Individual tubes connect and form a blood vessel loop in order to circulate blood. Muscle cells stabilize and support these tubes and blood flow begins.
The results of abnormalities in the angiogenesis process can cause many different diseases and even lead to cancer. The process is off when the pro-angiogenic molecules are balanced with the anti-angiogenic molecules but on when the balance is favoring one or the other. There are various factors that change or decide whether the process switches on. Either due to: metabolic stress (low pH levels), mechanical stress (pressure from other cells), immune/inflammatory response...