Based on the theory that shark cartilage may be effective in prevention and treatment of cancer, it has been known as nutritional supplement since a few years before. Shark cartilage has few blood vessels barely producing harmful substances. Angiogenesis such as generation of new capillaries are known to play a key role in the pathologic status of abscess, proliferative retinopathy, neovascular glaucoma, rheumatoid arthritis, and others. Also, it is important in phenomenon such as neovascularization accompanied by coronary arteriostenosis. In a study in 1976, Judag Folkman insisted that administration of shark cartilage partially inhibited the neovascularization and growth of abscess. Since anti-angiogenesis substances have been separated from the cartilage and studied, many studies are actively undertaken on the cartilage to discover the properties of vascular angiogenesis factors.
Sharks have endoskeleton generally composed of cartilage. When compared to the calf of which 0.6%of the total body weight is cartilage, 6% of the total body weight of shark is cartilage. Shark cartilages are mostly composed of collagen and proteoglycan just like any other cartilages. While collagen gives influence on the strength of muscles, proteoglycan gives elasticity to the cartilage. The major glycosaminoglycan included in the shark cartilage is chontroitin sulfate. Other than collagen and chondroitin sulfate, shark cartilages are composed of approximately 5~10% of water, lots of calcium and phosphate, and other compounds of small molecular weight.
Studies are currently undertaken on compounds of small molecular weight to verify their therapeutic effects on cancers and tumors. Some of these molecules have anti-angiogenesis and anti-tumor activities as well as inhibitory activity on metalloproteinase to suggest their value as a potential anti-cancer agent. Recently, shark cartilages have been experimentally used on progressed cancer in the late stage. In an experiment to test the safety in cancer treatment, shark cartilage has shown no activity without any beneficial effects on health. Neovastat(AE-941), an antianglogenic agent recently extracted from the deep sea shark cartilage, has been known to have protective actions in several stages in angiogenesis. In other animal models, oral administration of Neocastat (AE-941) has shown anti-tumor and anti-metastatic activities significantly. Since little side effects were observed in the long-term treatment in 800 patients for over 4 years, it is demonstrating good safety profile. Therefore, Neocastat(AE-941) has been reported appropriate as long-term anti-cancer agent. Clinical trials on kidney carcinoma patients in phase III and multiple myeloma patients in phase II are currently ongoing.
In several in vitro and in vivo experiments, shark cartilages have shown anti-atherosclerotic activity. In a recent clinical trial, shark cartilage extracts have prevented atherosclerosis. However, more data are needed to support the effectiveness.
Shark cartilages are expected to have beneficial effects in bone arthritis because they contain small amount of chondroitin sulfates. When tested in cancer patients, Neovatat(AE-941) included in the shark cartilage has delayed the spread, growth, and bone deformation to implicate the potential prevention of arthritis in cancer patients.
It is contraindicated to those with hypersensitivity to the compounds included in the shark cartilage and those with hypercalcemia. Pregnant and lactating women should avoid the administration of shark cartilage and patients with kidney or liver diseases should pay cautions to administration. Cancer patients who want to uptake shark cartilage must follow the physician’s order as appropriate. Side effects including gastro-intestinal track problems have been reported such as nausea, vomiting, stomach hypertrophy, constipation, and others. Some people hate the unique taste. A study on the hepatitis related to the shark cartilage has been also reported.