- The Washington Times - Wednesday, September 10, 2003

Artificial blood is an interesting technology that looks to be on the way to working.

The idea is obvious: If people lose a lot of blood in disasters or wars, and the medical folk don’t have enough real blood at hand, a substitute would be useful. Further, the use of real blood involves a lot of administrative overhead, such as collecting it, storing it, and making sure it isn’t contaminated by HIV and other infectious materials.

Only in recent years has medical science reached the point where artificial blood begins to look practical.

For a long time emergency personnel have administered fluids to expand the volume of blood in the circulatory system. This is different from artificial blood. The problem is that volume-expanders don’t carry much oxygen. The artificial bloods being developed by companies like Northfield and Biopure will carry oxygen. If they work.

Biopure has a product, Hemopure, that has been approved for human use in South Africa and is going through the approval process in the United States.

Artificial blood is expected to be used only until the body or doctors can replace it with the real thing. Natural blood is fantastically complicated and does things that a substitute can’t, like clotting.

Two basic approaches have gotten attention. One is the use of what are called perfluorochemicals. These (says Scientific American) can carry 50 times as much oxygen as plasma alone (plasma being the fluid in which red blood cells ride). So far they haven’t been very successful, though research continues.

The other approach is to use hemoglobin, the substance that carries oxygen in natural blood. Hemoglobin from cattle can be used. The problem is that in the bloodstream hemoglobin is contained with the membranes of red blood cells. If you just inject it into the body it can break down and become toxic.

On the other hand, the antigens molecules responsible for the type of a particular person’s blood (O, A, B, or AB) are found on the membrane. Since hemoglobin-based blood substitutes don’t have these antigens, emergency medical personnel wouldn’t have to worry about typing a patient’s blood.

Biopure uses cow hemoglobin in Hemopure, its blood substitute. Says the company, “Hemopure consists of chemically stabilized bovine hemoglobin formulated in a balanced salt solution. On a gram-for-gram basis, this cross-linked hemoglobin carries the same amount of oxygen as the hemoglobin in red blood cells.”

Northfield calls its product PolyHeme, and sees it as useful in shock-trauma clinics.

Advanced countries can collect, store, and type blood, as well as train technicians. Undeveloped countries often cannot do these things. For them, sterile out-of-the-box artificial blood that could be stored for long periods of time, would be a blessing. Northfield says PolyHeme can be stored for about a year if refrigerated.

My take on all of this is that we are going to see a lot more replacement of bodily parts and substances with artificial substitutes. The tech journals are full of reports of attempts to grow new organs and to use animal organs to replace human ones.

The computer explosion accustomed people to swift change. But you just can’t go that fast in biotechnology. What we are seeing is a dignified, deliberate headlong advance that is going to produce remarkable changes before long.



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