Shark cartilage is from the skeletal structure of
sharks. It is composed of 40% proteins, 5-20% glycosaminoglycans, and
calcium salts. Although it's exact mechanism of action is not know, three
principle mechanisms of action have been proposed to explain the ant--tumor
potential of cartilage:
- it kills cancer cells directly
- it stimulates the immune system
- it blocks the formation of new blood vessels
(angiogenesis), which tumors need for growth
There is limited evidence for the first two mechanisms
of action. The majority of the research has focused on the
anti-angiogenesis effects of shark cartilage.
Two proteins have been identified that are angiogenesis
inhibitors, SCF2 and U-995. U-995 has been reported to inhibit endothelial
proliferation, endothelial cell migration, and matrix metalloproteinase activity
in vitro. It does not seem to inhibit the proliferation of other types of
cells, such as cancer cells. SCF2 is a glycosaminoglycan whose principle
glycosamine is keratan sulfate. It has been shown to block endothelial
cell proliferation in vitro, to inhibit the formation of new blood
vessels in the chorioallantoic membrane of chicken embryos, and to also inhibit
the tumor-induced angiogenesis in the cornea of rabbits.
Neovastat (AE-941), the aqueous extract of shark
cartilage, has been found to posses similar qualities. It is not known
whether Neovastat derives these properties from one of the two above mentioned
angiogenesis inhibitor proteins, or whether other yet unidentified, but active
proteins are responsible. It is now in phase III clinical trials to try to
determine its exact anitcancer activity.
These findings have all been published in peer-reviewed, scientific
literature. |
