Angiogenesis Factors

Angiogenesis is the growth of new capillary blood vessels.

Angiogenesis is the growth of new capillary blood vessels in the body. It is a necessary process essential to healing and reproduction. Angiogenesis is controlled by a precise balance of inhibitory and growth factors within the tissue. When the factors are out of balance, the body produces either too many or too few blood vessels.

Introduction

The primary purposes of angiogenesis is to heal wounds and restore blood flow to injured tissues. In women, angiogenesis also takes place during the monthly reproductive cycle to rebuild the lining of the uterus, and during pregnancy. The body controls angiogenesis via a series of switches, according to angio.org. The "on" switches are referred to as the angiogenesis-stimulating growth factors, and the "off" switches are referred to as the angiogenesis inhibitors. When more growth factors are produced instead of the inhibitors, blood vessel growth increases. If more inhibitors are present, angiogenesis is stopped.

Function

There are more than 20 kinds of angiogenic growth factors in the human body. The specific way that the factors grow is still not entirely understood, according to biomed.brown.edu. However, scientists do know that diseased or injured tissues produce and release factors that then bind to specific receptors located on endothelial cells of the surrounding blood vessels. This process activates the endothelial cells and forces them to produce new molecules, including enzymes.

Features

The enzymes produced by the endothelial cells dissolve tiny holes in the basement membrane surrounding the existing blood vessels. When the endothelial cells begin to divide, they move out through the holes into the existing vessels. Adhesion molecules are specialized molecules that act like grappling hooks and pull the new blood vessel sprout forward, according to biomed.brown.edu. Additional enzymes are produced to dissolve the tissue in the front of the sprouting vessel so that the vessel can continue to extend forward. When the sprouting endothelial cells roll up, they form blood vessel tubes. These blood vessel tubes connect to form blood vessel loops that circulate blood.

Medical Research

The study of angiogenesis is a new medical approach to fighting disease, according to angio.org. For example, by utilizing treatments that either stimulate or inhibit growth of blood vessels, doctors are able to prolong the lives of patients suffering from cancer. Furthermore, medical treatments based on angiogenesis have also prevented limb amputations and reversed vision loss.

Treatments

All cancerous tumors release angiogenic growth factor proteins that stimulate blood vessels. These blood vessels are provided with oxygen and nutrients and as a result grow into tumors. Therapies that control these growth factors (called anti-angiogenic therapies) interfere with this process and prevent the tumor from accessing its blood supply. Another type of treatment is therapeutic angiogenesis, which stimulates growth factors where they are lacking. This is used to replenish the blood supply to chronic wounds to speed up healing and are widely used to save limbs from amputation. Furthermore, it is even applied to tissues previously thought to be impossible to rehabilitate (such as nerve and brain tissue).

References

• angio.org
• biomed.brown.edu