Tuesday, September 20, 2011

'Shark molecule' protects against many diseases

A molecule called squalamine seems effective against an unusual broad spectrum of diseases. It was already known that this molecule, which was originally isolated from sharks in 1993, is able to kill bacteria and protect the body against cancerous cells. Now, researchers have found that squalamine is also effective in preventing cells of being infected by a variety of viruses. In addition, it also prevents eye disease called macular degeneration. Compounds which are effective against multiple diseases are not rare, but squalamine's seems to be effective against diseases that are completely distinct from each other, making it an interesting potential therapeutic agent.

The scientists, working at the Georgetown University Medical Center, isolated squalamine molecules that assert their effects in the shark's liver. They found that squalamine is able to bind to the outer layer of the liver cell, called the membrane, where it neutralizes the negative electrical charge that is present. Viruses need this electrical potential in order to replicate effectively. Squalamine treatment  in cultured cells prevented, among others, infection with Hepatitis B, Dengue virus and the virus for Yellow Fever. A broad variety of viruses were tested. The scientists used hamsters for their experiments with squalamine, but due to the high efficacy, they hope human clinical trials for use as an antiviral agent can start within a couple of years.

Sharks have more than just the squalamine molecule that works in the liver. Comparable molecules are found with activity in kidney and lungs. One of the possible problems, however, is that squalamine treatment needs high dosis, which may be toxic for the body. Making squalamine derivatives with slightly different properties can possibly fix this problem, however the researchers do not note this. Squalamine can be synthesized and is already known to be safe for humans, further demonstrating its therapeutic potential.

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