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Blood alternative possible with added research
(CNN) -- Call it the new "cellophane."
Researchers at the University of Southern California are using a polymer coating to make red blood cells compatible for universal donation, a development that could radically change how blood is collected and used across the country.
"The ultimate goal is to take this technology and apply it to the whole blood supply so that every unit of blood that's given in the United States would be converted to a universal type before transfusion," said Dr. Timothy Fisher, an assistant professor in the department of physiology and biophysics at USC's Keck School of Medicine. "The polymer coating hides the blood group antigens so that the recipient's immune system can't recognize the foreign blood cells."
About 14 million units of blood are transfused every year in the United States, but shortages typically peak in the summer, during holidays and illness outbreaks.
"Our blood supply is really low ... because we haven't been able to have as big a drive for blood collection at places where people work, because people are on vacation," said Dr. Rebecca Haley, a senior medical officer at the national headquarters of the American Red Cross in Rosslyn, Virginia.
Even when supplies of donated blood are plentiful, there still may be risks. More than 300,000 people contracted Hepatitis C from contaminated blood transfusions before a test was developed to screen the blood supply.
"There's a potential for a huge volume of blood to be treated with the process," said Dr. Herbert Meiselman, a USC professor of physiology and biophysics.
In laboratory research, scientists Meiselman, Fisher and a colleague, Jon Armstrong, have used polyethylene glycol, or PEG, to mask blood type and protect the red cells from attack by the immune system. The coating is similar to the substance used to make soft contact lenses. It acts as a barrier, but is still able to allow oxygen and small molecules to pass through and diffuse to other cells -- a normal cell function.
The thin barrier also provides a "non-stick" coating for the red blood cells, allowing them to slide past one another and glide across blood-vessel walls to deliver oxygen to the tissues.
"Polymer coating prevents red blood cells from sticking to each other and the artery wall, so it could also be useful in patients who had had heart attack, stroke or vessel disease," said Fisher.
Preliminary tests also have shown the compound may be useful in treating sickle cell anemia by thinning the blood to increase flow and oxygen-delivery capacity. Tests in humans, however, could be at least five years away, the researchers estimated.
Another California company, Cerus Corp., is one of several testing new techniques to inactivate viruses and bacteria that can contaminate blood components such as platelets, plasma and red blood cells.
"We're going to be able to prospectively guard the blood supply against new viruses and bacteria, which will emerge and get into our blood in the future," said Cerus president and CEO Stephen Isaacs.
Research also continues on other blood substitutes, mostly made from hemoglobin (the substance in red blood cells which combines with oxygen) harvested from donated human blood that is too old for use and blood from cows. In addition, some scientists are focusing on using a form of genetic engineering to coax animal, bacteria or yeast cells to produce hemoglobin.
CNN Medical Correspondent Eileen O'Connor contributed to this report.
American Red Cross
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