Some studies suggest longer-stored blood units more likely to be associated with toxicity
Researchers in the University of Alabama at Birmingham (UAB) departments of Pathology, Microbiology and Surgery have received a $1.47 million grant from the National Heart, Lung, and Blood Institute (NHLBI) to study so-called red blood cell lesion, a term given to the potentially harmful changes in red blood cells that have been stored for longer times after collection.
The UAB study will focus on the mechanisms by which red blood cell storage time affects blood flow through capillaries, and whether the storage age impacts the interaction between banked red cells and nitric oxide produced in the body.
"We hope to shine a light on the mechanisms behind how red blood cells interact with nitric oxide during circulation to control blood flow and immune response, and see if this control is lost when red cells age in storage," says Rakesh Patel, Ph.D., associate professor of molecular and cellular pathology and lead investigator on the grant.
"The bottom line is we want to know all that we can about the possible negative effects of administering older stored red blood cells, and we hope this information can be used to design therapies to prevent transfusion-related toxicities," Patel says.
Blood processing and storage are known to cause several changes in red blood cell units, including lowering concentrations of molecules that regulate how oxygen is delivered to tissues once transfused. Currently, U.S. Food and Drug Administration regulations allow facilities to store red blood cells for up to 42 days before being transfused. The average age of transfused red blood cells in the United States is estimated to be a little more than 16 days.
UAB researchers will study injured patients in an intensive care unit who need transfusion with one unit of blood. They plan to match the storage age of the blood to several key measurements in recovering trauma patients, including circulation dynamics and inflammation markers in the blood. The grant is a partnership between Patel in the UAB Department of Pathology, Scott Barnum, Ph.D., in the UAB Department of Microbiology, and physicians in the UAB Department of Surgery.
Current data on red blood cell storage times and patient outcomes yield conflicting results. Some studies suggest longer-stored blood units are less effective and more likely to be associated with transfusion-related toxicity caused by red blood cell storage lesion. Other investigators have found no differences in clinical outcomes using red cells stored short-term or long-term.
The UAB grant is part of a larger award from the NHLBI, a part of the National Institutes of Health, to a total of nine investigator teams studying the safety and efficacy of red blood cell transfusions. One of the projects is the Red Blood Cell Storage Duration Study (RECESS), a large, multi-center randomized clinical trial to determine whether red blood cell storage time affects the postoperative outcomes of heart surgery patients. RECESS plans to enroll about 1,830 patients.
Most RECESS sites expect to begin enrolling patients in early summer 2010, although additional sites may be added later.
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