View full lesson: http://ed.ted.com/lessons/can-we-eat-to-starve-cancer-william-li William Li presents a new way to think about treating cancer and other dis...
|Scooped by Graham Player Ph.D.|
Cancer cells depend on blood supply for the nutrients they need to sustain their own life and develop into tumors. When solid cancers are small, they are supplied with nutrients by diffusion from nearby blood vessels. In order for a tumor to grow and metastasize, it must become vascularized through the action of angiogenesis.
Angiogenesis, the growth of new capillary blood vessels in the body, is an important natural process used for healing and reproduction. The body controls angiogenesis by producing a precise balance of growth and inhibitory factors in healthy tissues.
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).
In the healthy body, a series of biologic "on" and "off” switches help modulate angiogenesis.
- 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. In general, angiogenesis is "turned off" by the production of more inhibitors than stimulators.
The concept of angiogenesis as only being a localized phenomenon in tumor development has been modified as we now understand more about the other cell-types that are involved in tumor development. It is now known that angiogenesis for cancer growth is in fact a systemic effect. There are adult stem cells present in the bone marrow that are called into action by tumors, no matter where the tumor is located. The tumor mobilizes these cells that circulate in the blood stream so that they are drawn to the site of the tumor to initiate, support and fuel the growth of blood vessels for the tumor.
Angiogenesis inhibiting drugs were once thought to have potential as a silver-bullet treatment applicable to many types of cancer, but limitations were found to exist with anti-angiogenic drug therapy.
Research is now revealing that many naturally occurring foods are as good, and in some cases better, than drugs in the control of angiogenesis. This is a major step forward in the strategies we have at our disposal for cancer prevention. To learn more visit the Angiogenesis Foundation - http://www.angio.org/
For a list of the dietary sources of naturally occurring anti-angiogenic foods see here - http://blog.ted.com/2010/02/10/dr_william_lis/