September 22, 2011

Shark Compound Treats Viruses?

(Ivanhoe Newswire) -- A compound that was initially isolated from sharks may serve as an antiviral treatment, according to a new study.

The compound -- known as squalamine -- has been studied in human clinical trials for treating cancer and eye disorders. In both lab and animal studies, the compound showed antiviral activity against human pathogens.

"To realize that squalamine potentially has broad antiviral properties is immensely exciting, especially since we already know so much from ongoing studies about its behavior in people," the study's lead investigator, Michael Zasloff, M.D., Ph.D., professor of surgery and pediatrics at Georgetown University Medical Center and scientific director of the Georgetown Transplant Institute, was quoted as saying.

Dr. Zasloff first discovered squalamine in 1993 when he was searching for antibacterial agents and became interested in sharks because of their immune systems. Since 1995, squalamine has been synthesized in the lab -- a process that does not involve the use of any natural shark tissue.

"I believe squalamine is one of a family of related compounds that protects sharks and some other 'primitive' ocean vertebrates, such as the sea lamprey, from viruses," Dr. Zasloff said.

"Squalamine appears to protect against viruses that attack the liver and blood tissues, and other similar compounds that we know exist in the shark likely protect against respiratory viral infections, and so on."

Dr. Zasloff sent the compound to researchers around the country. In tissue culture studies, squalamine was shown to inhibit the infection of human blood vessel cells by the dengue virus and human liver cells infected with hepatitis B and D, which can cause liver failure and cancer. In animal studies, researchers found squalamine controlled infections of yellow fever, Eastern equine encephalitis virus, and murine cytomegalovirus, and in some cases, cured the animals.

"We have not yet optimized squalamine dosing in any of the animal models we have studied, and as yet, we do not know the maximum protective or therapeutic benefit that can be achieved in these systems," Zasloff said."But we are sufficiently convinced of the promise of squalamine as an antiviral agent that we intend to take this compound into humans. It is clearly a promising drug, and is unlike, in its mechanism of action and chemical structure, any other substance currently being investigated to treat viral infections."

SOURCE: Proceedings of the National Academy of Sciences, September 19, 2011