Compound Found in Sharks Has Anti-Viral Potential

Sharks and antiviral medications may seem like they have nothing in common. Au contraire mon ami, you may be surprised to know that sharks are at the cutting edge of viral research. A study published in the Proceedings of the National Academy of Sciences reports that a compound in sharks has the potential to be used as a "broad spectrum" antiviral agent in humans.

Doctor Zasloff eventually recognized that squalamine could also be used to combat viruses. Squalamine's virus-killing abilities are attributed to its positive charge. When squalamine enters a cell it adheres to the cell's negatively charged inner membrane. In the process squalamine knocks off positively charged proteins that cling to the inner membrane. While squalqmine in no way hurts cells its actions do hinder viruses. Viruses require the proteins on the inner membranes in order to reproduce in cells. Doctor Zasloff notes sthat "there is no other compound known to science that does this-this is a remarkable property."

This "remarkable property" has benefited sharks for millions of years. Now scientists are hopeful that squalamine can benefit humans too. Multiple tests involving squalamine as an antiviral have had promising results. The compound successfully prevented dengue fever virus infection in human blood vessels and Hepatitis B and D infection in human liver cells. In animal trials squalamine warded off yellow fever, eastern equine encephalitis virus, and murine cytomegalovirus. Researchers were unable to test squalamine against Hepatitis C, which affects 150 million people globally, because it grows poorly in lab animals. Instead, yellow fever was used as a stand in model for Hepatitis C. Thankfully, squalamine's benefits can be reaped without killing sharks. Since 1995 the compound has been produced artificially in the laboratory.

Squalamine's effectiveness against several viruses gives it a desirable advantage over current antiviral drugs. Today's antiviral drugs only target one specific virus. The problem with this is that viruses are always mutating and will eventually become drug resistant. Scientists hypothesize that viruses are less likely to become resistant to squalamine since it stops the viruses from infecting the cells rather than "attacking viral proteins."

The authors of the study intend to start human trials with squalamine soon. However concerns have been raised in regards to squalamine's toxicity. Todd Rider of MIT says that squalamine "does have some toxicity and other side effects in certain cell types at doses roughly comparable to those that were required for antiviral efficacy." Further tests will need to be performed to see if squalamine can still prevent viral infection at non-toxic dosages. Doctor Zasloff remains optimistic about squalamine's potential and argues that most antivirals are somewhat toxic. He adds that additional trials will show if squalamine can be administered to humans safely.

I think it is really fascinating that a compound originally found in sharks could hold such promise in the field of viral prevention. This discovery really demonstrates the interconnectedness of the animal world. On a side note, Ohr Pharmaceutical is testing a medication for the treatment of wet macular degeneration (an eye condition) containing squalamine.

Refrences:

BBC. "Dogfish shark chemical squalamine 'stops human viruses'" BBC News. September 20, 2011.

Dell'Amore, C. "Sharks' Virus Killer Could Cure Humans, Study Suggests." National Geographic. September 19, 2011.

Georgetown University. "Shark Compound has potential to treat human viruses." Georgetown University. September 19, 2011.

Welsh, J. "Shark Molecule Kills Human Viruses, Too."Live Science. September 19, 2011.

Multimedia Credits:

1. Spiny Dogfish: National Oceanic and Atmospheric Administration (via Wikimedia Commons)

2. Video: C&EN