Types and sources of fuels for platelets in a medium containing minimal added fuels and a low carryover plasma

The storage of platelets in synthetic media can result in plasma savings and reduced transfusion reactions. Accordingly, a wide range of storage formulations have been developed with the aim of replacing at least a proportion of the plasma in the storage medium. However, the concentrations and types of fuels in the carryover plasma, and the utilization of these fuels by platelets in storage, has not been investigated. We have developed a system which can measure total ATP turnover, and the contribution to total ATP turnover by the oxidation of various fuels and by lactate production, in a bag of partially purified platelets in a buffered saline with minimal carryover citrate phosphate double dextrose (CP2D) plasma. Carryover plasma was about 1% and the final platelet suspension contained, on average, 0.62 mM glucose, 9.6 mg/l free fatty acids, 32 mg/l triglycerides and 0.23 mM total amino acids. The oxidation of carbohydrate (glucose, glycogen and lactate) accounted for 60% of total ATP turnover. The platelets also produced lactate (<6% of total ATP turnover) and consumed free fatty acids and amino acids/proteins (15.2% of total ATP turnover). Therefore we have identified the fuels that account for about 80% of oxygen consumption and ATP turnover by platelets in a medium with low carryover plasma. The implications of these data for storage strategies are discussed.