Angiogenesis (angio'genesis) - the growth of new blood vessels - is an important natural process occurring in the body, both in health and in disease.

The Body's Control of Angiogenesis
Angiogenesis occurs in the healthy body for healing wounds and for restoring blood flow to tissues after injury or insult. In females, angiogenesis also occurs during the monthly reproductive cycle (to rebuild the uterus lining, to mature the egg during ovulation) and during pregnancy (to build the placenta, the circulation between mother and fetus).

The healthy body controls angiogenesis through a series of "on" and "off" switches:
• The main "on" switches are known as angiogenesis-stimulating growth factors
• The main "off"  switches are known as angiogenesis inhibitors

When angiogenic growth factors are produced in excess of angiogenesis inhibitors, the balance is tipped in favor of blood vessel growth. When inhibitors are present in excess of stimulators, angiogenesis is stopped. The normal, healthy body maintains a perfect balance of angiogenesis modulators.

Excessive Angiogenesis
• Occurs in diseases such as cancer, diabetic blindness, age-related macular degeneration, rheumatoid arthritis, and psoriasis, and more than 70 other conditions.
• In these conditions, new blood vessels feed diseased tissues, destroy normal tissues, and in the case of cancer, the new vessels allow tumor cells to escape into the circulation and lodge in other organs (tumor metastases).
• Excessive angiogenesis occurs when diseased cells produce abnormal amounts of angiogenic growth factors, overwhelming the effects of natural angiogenesis inhibitors.
• Anti-angiogenic therapies, aimed at halting new blood vessel growth, are being developed to treat these conditions.

Insufficient Angiogenesis
• Occurs in diseases such as coronary artery disease, stroke and delayed wound healing.
• In these conditions, inadequate blood vessels grow and circulation is not properly restored, leading to the risk of tissue death.
• Insufficient angiogenesis occurs when the tissue cannot produce adequate amounts of angiogenic growth factors.
• Therapeutic angiogenesis, aimed at stimulating new blood vessel growth with growth factors, is being developed to treat these conditions.