Can HSC scientists quench the blood shortage with a formula of their own?
by Amanda GallagherA creaky oil derrick taps into the earth, dredging out what some call black gold, Texas Tea – oil that fuels our homes, feeds our gas tanks and sits at the center of global controversy.
Some would argue it is our most precious resource. Yet there is another liquid that is far more expensive, far more important, and far more difficult to come by. It is human blood. "Blood is a lifesaving fluid. It is liquid life," said Vibhudutta Awasthi, Ph.D., an assistant professor in the department of radiology. It is also liquid gold.
Hospitals pay roughly $149 a pint for red blood cells; a pint of oil runs approximately 78 cents, depending on market value. And while conservative estimates say the world has between 1.8 trillion and 2.4 trillion untapped barrels of oil, experts predict hospitals will see a 4 million unit-a-year blood shortage by 2030. Without an ample supply, doctors face tragedy in the operating room and soldiers face death on the battlefield.
That is why the U.S. Office of Naval Research awarded William T. Phillips, M.D, and Beth A. Goins, Ph.D., a $1.45 million grant to develop a blood substitute. "Regular blood is best," Dr. Phillips said. "But if you could have a blood substitute in every ambulance, in every operating room, in every military hospital, you could potentially save a lot of time and thousands of lives."
The Health Science Center is one of only a handful of institutions making a blood substitute and may be leading the global pack. "This is the closest weíve been to developing a non-toxic, long-circulating blood substitute," Dr. Phillips said. "No one has approved a blood substitute in the United States, but the blood substitutes other companies have made only stay in the blood about 12 hours. The average circulation of the one we developed is 60 hours."
Dr. Phillips and Dr. Awasthi, a co-investigator on the grant, are using an encapsulation process that not only will replenish the dwindling blood supply, it will recycle natural blood that hospitals canít use. "We are making the blood substitute out of hemoglobin that comes from discarded red blood cells. Blood banks have to get rid of the red blood cells after about 42 days, so we are really recycling what we already had in our limited blood supply," Dr. Awasthi said.
Hemoglobin is the oxygen-carrying protein found in red blood cells. Scientists have tried directly injecting it into the bloodstream, but it breaks down and becomes toxic. Instead, Drs. Phillips and Awasthi are encapsulating the hemoglobin in lipid spheres--tiny bubbles formed from fats.
"The lipid sphere mimics a red blood cell. It encapsulates the hemoglobin so the rest of the body doesnít see it, but it still enables the hemoglobin to deliver oxygen throughout the body," Dr. Awasthi said.
Some scientists prefer to call the blood substitute an oxygen-carrying system because that is primarily what it does. "Whole blood is made of four parts that have other functions such as clotting and fighting infections," Dr. Phillips said. "But trauma patients usually die from a lack of oxygen. The blood substitute enables tissues to receive oxygen until doctors can control a patientís bleeding. Once the patient is stabilized, doctors can transfuse natural blood."
Since the blood substitute has a circulation of 60 hours, it gives doctors the unusual luxury of time. "It takes about 30 minutes to an hour to match a patientís blood type," Dr. Awasthi said. "You donít have to match the blood substitute, and after a patient has it, it gives doctors at least another day to find a match. To a dying person, that could be a lifetime."
The blood substitute is almost the same consistency as ordinary blood, but it doesnít quite look like it. The batch in Dr. Awasthiís refrigerator resembles a light tomato soup – and has a shelf life thatís almost as long.
"Without any stabilizers, we can store the blood for about three months. We havenít tested the shelf life beyond that, but webelieve we can preserve it for up to six months," Dr. Phillips said.
Thatís nearly three to four times longer than natural blood is stored. But itís not just the shelf life that is so impressive. Itís the potential for storing capacity. "We are studying ways to condense the formula so itís more portable. For instance, we are looking at a process to make a paste that we can store in a tube. Doctors would just add sterile water when they needed to use it," Dr. Awasthi said. The idea could have major implications for deployed military units with very limited storage space.
Drs. Phillips and Awasthi also want to use the substitute in organ transport. Emergency technicians usually pack donated organs on ice to slow their death. The blood substitute may actually keep organs alive longer by providing oxygen while removing carbon dioxide.
So far, the blood substitute has only been tested in animal models; its use in humans is still a few years off. But it is desperately needed. "Ailments you can cure, but blood? You can only replace it," Dr. Awasthi said. With that in mind, his refrigerated formula truly is liquid life.
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