Blood from plants

Plants have been used in medical treatments throughout human history, but researchers have been looking to the world of biotechnology for new solutions to lingering medical conditions. One such solution is a human blood protein now being cultivated in a genetically-modified tobacco plant.

Researchers at the Department of Energy's Pacific Northwest National Laboratory are taking a new approach to plants as pharmaceutical components. They are genetically modifying plants to produce human blood proteins and tissue growth agents.

These blood-clotting agents could lead to safer and less expensive treatments for hemophiliacs and an alternative way of sealing wounds. Pacific Northwest researchers have produced two blood factors that are used to treat most patients with blood clotting disorders.

Researchers are synthesizing human coagulation factor VIII, an ingredient in human blood that helps stop bleeding. Consequently, it's a much-needed protein for people with hemophilia and other blood-clotting disorders.

These factors currently are made from human blood plasma or by painstakingly cultivating mammalian cells. But treatments derived from human or animal components can be risky. For instance, about 80 percent of hemophiliacs over the age of 10 were infected with HIV from receiving blood products prior to the development of screening programs.

Even with screening programs some viral products such as HIV, Epstein-Barr, Hepatitis B and C and even the flu, can be transferred in blood products. Using plants to produce human blood proteins eliminates the possibility of transmitting disease along with lifesaving treatments.

"In addition to the obvious health benefits, we expect the cost of synthesizing blood factors in transgenic or genetically modified plants to be 10 times cheaper than current methods," said Brian Hooker, a biochemical engineer at Pacific Northwest. "And, unlike human blood donors or mammalian cells, plants provide a stable production source and yield much higher amounts of the desired blood factors."

Dr. Brian Hooker is the man who's been working on cultivating the factor VIII protein. He does this by putting the factor eight gene into what's called an agrobacterium - a solution that allows genes to be transfered to plants. The genes carry a kind of blueprint which instructs an organism on how to create the protein. 

"We'll take what's called a leaf disc from tobacco, and then we'll take a very dilute solution of the agrobacterium and we cultivate the agrobacterium with the tobacco leaf discs." 

After three or four days in solution, the discs become infused with the factor eight gene. They can then be removed and cultivated. 

"We'll place these in a petri dish containing a nutrient medium and wait for a period of over two to four weeks and we'll see individual roots start to form on these leaf discs, individual shoots form on these leaf discs, and eventually we can scale that up into a full genetically-modified tobacco plant." 

The final step in obtaining factor eight from the plant is grinding up the tobacco leaves and extracting the juices which contain the protein in solution. 

Using genetic engineering technology, Pacific Northwest researchers are transplanting applicable human genes into tobacco plants and producing blood factors. Patents are pending on the production and composition of plant-derived human blood coagulation factors. Pacific Northwest researchers have produced coagulation factor VIII, which is critical to hemophilia therapies, as well as factor XIII and a substance called thrombin which are clotting enzymes that aid in healing wounds and offer an alternative to sutures and other surgical sealants.

Pacific Northwest has funded this research to date but is interested in teaming with pharmaceutical partners to commercialize the blood factor technology and other plant-based pharmaceutical products. Commercialization manager Daniel Anderson says it likely will be several years before the blood products will be available for humans.