Blood vessels are comprised of cells called "endothelial
cells." The total surface area covered by these cells in an adult
is 1000 m2, roughly the size of a tennis court.
If all the blood vessels in the body
were lined up end-to-end, they would form a line that could circle the
Blood vessel cells do not normally
grow in the healthy adult, they are normally inactive, or quiescent.
There are more than 19 known angiogenic
Five of the angiogenic growth factors
are being tested in humans for growing new blood vessels to heal wounds
and to restore blood flow to the heart, limbs and brain.
The first commercially-available
angiogenic growth factor is PDGF-BB (platelet-derived growth factor-BB,
Regranex™) used to speed healing in chronic wounds.
Angiogenic gene therapy is also being
developed as a method to deliver angiogenic growth factors to the heart,
limbs and wounds.
There are at least 30 known natural
angiogenesis inhibitors found in the body.
The first angiogenesis inhibitor
molecule was discovered in 1975 by Drs. Henry Brem and Judah Folkman during
their study of cartilage.
Angiogenesis inhibitors have been
discovered from natural sources, including tree bark, fungi, shark muscle
and cartilage, sea coral, green tea and herbs (licorice, ginseng, cumin,
In total, more than 300 angiogenesis
inhibitors have been discovered to date.
As many as 150 million patients in
Western nations could benefit from some form of antiangiogenic therapy.
At least 300 million patients in
Western nations would benefit from some form of angiogenesis-stimulating
The first successful treatment of
an angiogenesis-dependent disease occurred in 1989, when the drug interferon
alfa2a, an angiogenesis inhibitor, was used to regress the abnormal blood
vessels growing in the lungs of a boy with a benign disease called pulmonary
At least 6,500 cancer patients have
been treated with some form of experimental antiangiogenic therapy.
Some cancer patients have experienced
dramatic regression of their tumor from antiangiogenic therapy; others
have experienced stabilization of their disease.
More than 1,000 patients with heart
disease have received some form of experimental angiogenic therapy.
The first FDA-approved device to
stimulate new blood vessels to grow in diseased hearts is a laser used
in a technique called Direct Myocardial Revascularization.
The first FDA-approved blood vessel
therapy for eye disease is a type of photodynamic therapy called Visudyne
(QLT Therapeutics/CibaVision), which has shown effectiveness for treating
The first FDA-approved angiogenesis-stimulating
medicine is a wound healing gel called Regranex (recombinant human platelet-derived
growth factor-BB, Ortho-McNeil Pharmaceuticals) which was FDA-approved
to treat diabetic foot ulcers in December 1997.
An estimated $4 billion has been
invested in the research and development angiogenesis-based medicines,
making this one of the most heavily funded areas of medical research in
DOBI Medical International would like to thank Dr. William
Li and the Angiogenesis Foundation for providing much of the information
presented above. For more information on the Angiogenesis Foundation,
please visit www.angio.org.