Researchers in the Boston area are focusing their attention on attempting to extend the shelf life of platelets from the current five days.

In a recent issue of Science, a team of researchers from Harvard University and Brigham and Women's Hospital reported that putting a small amount of galactose, a type of sugar, into isolated platelets allows this blood component to be refrigerated and usefully preserved for at least 12 days. This more than doubles the shelf life using the current practice of storing the platelets at room temperature for just five days.

Platelets are very fragile cell fragments. Currently if they are refrigerated in the same manner as whole blood, the platelets undergo a chemical change that makes them the target of one of the body's immune cells known as macrophages. When chilled platelets are transfused, they are engulfed and killed by the macrophages. For this reason, platelets are stored at room temperature, but lose their viabiity after five days. The macrophages attack chilled platelets because the immune cells target another type of sugar on the surface of the transfused platelet. Adding galactose covers up that other sugar and protects the platelets from the macrophages.

The technique has been tested in mice and in test tube studies using human platelets. The next step will be to test the viability of the sugar-coated, chilled platelets in laboratory primates. Should the primate tests prove successful, the researchers would then apply to the Food and Drug Administration to test the system on humans. The cinical trials using humans could take two to three years to complete.

Members of the blood banking community will be following these studies with great interest. Should the clinical trials prove to be successful, this would be an important advancement in transfusion medicine.

Medical Update