Extended storage and glucose exhaustion are associated with apoptotic changes in platelets stored in additive solution

BACKGROUND: The storage of platelets (PLTs) in additive solution (AS) may facilitate improved PLT quality and possibly extension of the PLT shelf life. A minimum amount of plasma is required when PLTs are stored in AS, as a source of glucose. The aim of this study was to assess the effect of reducing the plasma carryover to 20% on PLT quality when stored in SSP+ for an extended period. STUDY DESIGN AND METHODS: Using a pool-and-split design, buffy coat-derived PLTs were stored in either 30% plasma/SSP+ or 20% plasma/SSP+. In vitro analyses were carried out to Day 10. Metabolites and markers of PLT activation and apoptosis were measured using a blood gas analyzer and flow cytometry. PLT apoptotic protein expression was investigated by Western blotting. RESULTS: Glucose exhaustion occurred in the 20% plasma group between Day 7 and Day 10. The surface expression of P-selectin and PAC-1 was comparable on Day 10 in both groups, suggesting that the PLTs were not activated. However, the exposure of phosphatidylserine and the number of phosphatidylserine-positive microparticles were significantly higher in the 20% group on Day 10. The expression of the proapoptotic proteins Bak, Bax, and cleaved caspase-3 were higher in the 20% plasma group by Day 7 of storage, compared to the 30% plasma group. CONCLUSION: Exhaustion of glucose was associated with a proapoptotic phenotype. Results such as these should be considered before extending the PLT shelf life beyond 7 days, particularly when stored in ASs lacking glucose with low plasma carryover.