Researchers at the UK’s University of Southampton and U.S. biotech company AquaGene have created a genetically modified fish which produces the human blood clotting agent factor VII.
Factor VII is used to treat a rare form of hemophilia as well as being used to treat gunshot wounds.
Currently factor VII is available commercially as NovoSeven — an injectable factor VII made from genetically modified hamster cells. Unfortunately growing hamster cells is surprisingly expensive, and a single injection of NovoSeven can cost up to $10,000.
Producing factor VII in fish would be much cheaper because researchers can achieve higher yields of the protein. According to researcher Norman Maclean,
Each milliliter of human blood has about 500 nanograms of the protein. We were able to match that yield in the blood of our fish.
Maclean has produced several variants of the fast-growing freshwater fish tilapia which are genetically modified to secrete factor VII from their livers and into their bloodstreams.
Maclean and AquaGene must now prove to the satisfaction of health agencies that the factor VII produced by the genetically modified fish is similar enough to human factor VII and that it is safe to use in humans before clinical trials could begin.
Interestingly, animal rights activists frequently claim that human beings are just too different from animals for things like NovoSeven or this new fish-derived effort to work. In this case, though, it is the difference between animals and human beings that makes using animals as a source for factor VII attractive.
Factor VII can be derived from human sources, but it requires expensive filtering to ensure that no human diseases are passed between the donor and the ultimate recipient. So far, there is no evidence that diseases can be passed from factor VII derived from hamsters or fish, making animal-based products superior to the human-based alternatives.
Source:
GM fish produce cheap blood-clotting agent. New Scientist, September 8, 2004.