Earlier this month, a blood substitute called HBOC-201 made headlines when it saved an Australian woman's life after a car crash. However, Jonathan Jahr, a professor of clinical anesthesiology at University of California, Los Angeles, says that synthetic blood has a long history: "Blood substitutes have been tested and thought about for probably a hundred years."
The basic technique that led to HBOC, or hemoglobin-based oxygen carriers, was first published in the 1930s. William Amberson, a physiologist at State College of Medicine in Memphis, Tenn., took red blood cells from cows and stripped away the cells' coating, leaving the oxygen-carrying molecule hemoglobin. Reintroducing the hemoglobin into a patient's blood supply proved an effective therapy, at least temporarily. At first it revitalized patients, but, in about 10 days, the small HBOC molecules caused kidney failure.
HBOCs have come a long way in 80 years, but they still have side effects. Jahr has studied several blood substitutes, including HBOC-201, known commercially as Hemopure. It is approved for use in humans in South Africa and Russia, and Oxyglobin, which has Food and Drug Administration approval for use in dogs, uses a chemically modified "polymerized" version of the HBOC to avoid renal failure.
Jahr doesn't foresee Hemopure's approval for widespread use in the United States, given side effects such as jaundice and a tendency to increase pancreas enzymes. But he believes that it might find approved use for patients who cannot accept donated blood for religious or medical reasons and in certain surgical procedures.
Embryonic stem cells, which can shape-shift into a variety of cell types, might prove one way to make up for shortfalls of donated blood. That's the hope of Robert Lanza, the chief scientific officer at Advanced Cell Technology, headquartered in Santa Monica, Calif. His team is working to make a large supply of the "universal" blood type—O negative—which any patient can use. "That's important when there is massive blood loss, especially on the battlefield, where there just isn't time for typing," Lanza says.
Advanced Cell Technology reported in 2008 that it had produced an unprecedented 10 billion red blood cells from human embryonic stem cells. It's an impressive step, but an early one: More work remains to create the trillions of cells required for transfusion, and to show that the cells will function normally when transfused. Lanza says that his company will soon seek approval for such testing.
If the company can create a new blood supply it will certainly catch the attention of the military, Lanza says, noting that the Defense Advanced Research Projects Agency (DARPA) is funding projects to make a system for blood delivery on the battlefield. "The goal here isn't to put the Red Cross out of business," he says. "Donated blood is always the first line of defense. But with this technology, you would have a safety net."