Angiogenesis, << `an jee` oh JEHN uh sihs, >> is the formation and growth of new blood vessels in the body. Angiogenesis plays an important role in the growth of tissues and the repair of tissues from wounds or infection. Abnormal angiogenesis, however, occurs in a variety of diseases. Excessive angiogenesis occurs in cancer and an eye condition called macular degeneration. Insufficient angiogenesis can occur following stroke.
Angiogenesis is caused by substances called angiogenesis-stimulating growth factors. One of these, called vascular endothelial growth factor (VEGF), is produced during growth or by injury or disease. In wounds, production of VEGF is stimulated by the lack of oxygen in tissue that does not receive enough blood. VEGF can also be used as a drug to stimulate blood vessel growth to help heal damaged tissues.
Cancer cells secrete chemicals that promote angiogenesis. The new blood vessels support the growth of the abnormal, rapidly dividing cells into larger tumors. The new blood vessels also allow cancer cells to spread to other sites in the body. Scientists are testing chemicals that inhibit (block) or promote angiogenesis in an effort to develop drugs to treat diseases in which abnormal angiogenesis occurs. In 2004, the United States Food and Drug Administration approved an angiogenesis-inhibiting drug for treating colon cancer. The drug is marketed under the name Avastin.
See also Cancer; Macular degeneration; Thalidomide.
