Apyrase, ascorbic acid and aprotinin ameliorate the storage lesion in pelleted platelet preparations.

To evaluate the effect of apyrase, ascorbic acid and aprotinin (AAA) in preventing platelet activation during storage, 12 sets of platelet concentrates (PCs), were treated with AAA and evaluated at days 1, 3, and 5 utilizing platelet functional and morphological assays. Platelets treated with AAA demonstrated significantly enhanced response to ADP-induced platelet aggregation, higher morphology scores, and evaluated ATP levels compared to control samples after 5 days of storage. Similarly, platelet specimens treated with AAA had significantly reduced PF4 secretion and P-selectin expression compared to controls. Finally, Western blots of aggregated platelets at day 5 demonstrated that AAA-treated PCs continue to express the platelet membrane GPIb whereas specimens from control PCs do not. These results show that PCs treated with AAA have reduced platelet activation and enhanced functional platelet activity.

Buffy coat platelets stored in apyrase, aprotinin, and ascorbic acid in a suspended bag: combined strategies for reducing platelet activation during storage.

BACKGROUND: Platelet activation is an important factor impeding the clinical effectiveness of platelet transfusions. In this study, platelet concentrates (PCs) were prepared by a novel suspended-bag buffy coat technique that was followed by the addition of a mixture of platelet activation inhibitors to the storage bag. STUDY DESIGN AND METHODS: In vitro platelet function was evaluated in PCs prepared by the suspended-bag buffy coat technique and stored at 22 degrees C for 5 days in the presence of (n = 12) or absence (n = 12) of apyrase, ascorbic acid, and aprotinin (AAA). RESULTS: Platelets from AAA-incubated PCs demonstrated mean ATP levels 17 percent (p < 0.004), 13 percent (p < 0.02), and 22 percent (p < 0.003) higher than those measured in parallel control PCs on Days 1, 3, and 5, respectively. Similarly, on Days 3 and 5 of storage, respectively, 45-percent (p < 0.001) and 50-percent (p < 0.001) greater ADP-induced maximum aggregation was observed in AAA-incubated PCs than was seen in control preparations. AAA-incubated PCs demonstrated alpha-granule membrane protein-140 expression 92 percent (p < 0.01), 133 percent (p < 0.003), and 104 percent (p < 0.001) below that in control PCs on Days 1, 3, and 5, respectively. At similar intervals, a significant increase in recovery from hypotonic shock also was observed in AAA-incubated PCs. Further, Day 5 AAA-PCs demonstrated significantly higher morphology scores and O2 consumption than did control preparations. CONCLUSION: Buffy coat platelets prepared in suspended bags and stored in the presence of AAA demonstrate significantly reduced activation and enhanced functional and metabolic activity.

A novel technique for preparing improved buffy coat platelet concentrates.

We evaluated in vitro platelet function of platelet concentrates stored at 22 C for 5 days prepared either by the conventional pelleting procedure or platelet concentrates prepared from buffy coats by utilizing a novel bucket designed to support a suspended bag. For platelet concentrates from buffy coat, whole blood was centrifuged at 3,000 x g for 13 min, with all but 30cc of the cell poor plasma transferred to a satellite bag, followed by a second centrifugation at 170 x g for 5 min utilizing our novel centrifugation device. For pelleted platelets, whole blood was centrifuged at 2,000 x g for 3 min, platelet rich plasma removed, centrifuged, and the pellet resuspended in plasma. Leukocyte contamination in buffy coat platelet concentrates was reduced by 95% (p < 0.001) in comparison to pelleted platelets. Further, platelets from buffy coat platelet concentrates demonstrated significantly enhanced ADP-induced aggregation, increased recovery from hypotonic shock, higher morphology scores, and reduced GMP-140 expression in comparison to pelleted preparations. No differences in O2 consumption, CO2 production, pH and total ATP were observed between the two types of preparations at day 5 of storage. Our results indicate that platelet concentrates from buffy coat, prepared by a suspended storage bag centrifugation technique, are superior with respect to in vitro platelet function when compared to pelleted platelets.