Quality assessment of platelet concentrates supplemented with second-messenger effectors

BACKGROUND: While reducing the potential for bacterial contamination, the storage of platelet concentrates (PCs) at refrigerated temperatures is not routine, because of the induction of the so-called platelet storage lesion. As the modulation of second-messenger levels might help to overcome this drawback, a quality assessment of PCs treated with a mixture of second-messengers effecters known as ThromboSol was performed. STUDY DESIGN AND METHODS: The PCs were supplemented with ThromboSol or phosphate-buffered saline, and stored in parallel at 22 degrees C with continuous agitation or at 4 degrees C. At 1, 5, and 9 days, an in vitro quality assessment of the PCs was performed, including measurement of cell number, metabolic and integrity markers, platelet surface expression of glycoproteins, platelet response to ristocetin and thrombin, and levels of cyclic adenosine 3',5' monophosphate (cAMP) and thromboxane B-2 (TxB(2)). RESULTS: Control PCs stored at 4 degrees C underwent aggregation and displayed a significant decrease in the platelet number (40% on Day 5). By contrast, the ThromboSol-treated PCs maintained 80 percent of their initial platelet concentration after 9 days of storage at 4 degrees C. Compared to PCs stored at 22 degrees C, refrigerated PCs exhibited minor changes in metabolic values throughout storage, but the addition of ThromboSol induced a rise in metabolic rate during storage at 22 degrees C. Platelet responsiveness to both ristocetin and thrombin was maximally preserved in the ThromboSol-treated PCs stored at 4 degrees C. These units also maintained high levels of cAMP and low concentrations of TxB(2) during storage. CONCLUSION: The pharmacologic supplementation of PCs with ThromboSol significantly favors the maintenance of in vitro integrity and responsiveness of platelets during extended storage at refrigerated temperature. This protective effect seems to be a consequence of the ability of ThromboSol's components to sustain high levels of cAMP and to inhibit TxB(2) production during the entire extended-storage period.