Extended Storage of Platelets in an Artificial Medium with the Platelet Activation Inhibitors Prostaglandin E1 and Theophylline1

Abstract

The addition of platelet activation inhibitors to the anticoagulant and the replacement of plasma with a fortified electrolyte medium have been shown separately in previous work to improve the storage of platelets during a 2-week period. In the present study, we have combined these strategies to investigate whether a synergistic improvement could be obtained. A total of 85 concentrates was studied with 300 nM prostaglandin E1 (PGE1) and 1.9 mM theophylline added to the whole blood, platelet-rich plasma (PRP), and/or the storage medium during the preparation of platelet concentrates. In vitro markers of platelet aggregation, respiration, and cell integrity were measured over a 20-day storage period and evaluated in an analysis of variance. We found that a single-step addition of PGE1 and theophylline to the PRP prior to centrifugation was not sufficient in terms of preventing a rapid fall in pH, rise in pO2, fall in pCO2, loss of hypotonic shock response, and loss of aggregation response, compared to the addition of the inhibitors to the storage medium used to resuspend the platelet pellet. Factorial analysis showed that a reduction in the surface-to-volume ratio of the storage container further improved the maintenance of platelet respiration and, for three in vitro markers (hypotonic shock response, released lactic dehydrogenase, and surface glycoprotein Ib levels) displayed an interactive effect with the inhibitors. The addition of protease inhibitors to the formulation of PGE1 and theophylline showed further improvement in several markers. These findings demonstrate the possibility of preserving platelets for 15-20 days with the synergistic effects of activation inhibitors and an electrolyte storage medium fortified with citrate, buffers, and dextrose.(ABSTRACT TRUNCATED AT 250 WORDS)