Background: Platelet (PLT) collection and storage affect the functional capacity of PLTs in PLT concentrates (PCs). Therefore, PLTs' functional quality should be studied before transfusion.
Study design and methods: PCs (n = 15) were collected by a standard apheresis procedure (Trima, Gambro BCT) and were stored for 7 days. Samples were taken to assess PLT adhesion and aggregate formation by a cone and plate analyzer (Impact-R, DiaMed) on Days 1, 3, 5, and 7 after harvesting. This device allows testing PLT function under high-shear stress close to physiologic conditions. Concomitantly, P-selectin expression and the residual responsiveness to TRAP-6 were determined by flow cytometry.
Results: PLT adhesion, as measured by surface coverage, decreased during the entire observation period; likewise, the size of aggregates was significantly lower on Days 5 and 7 compared to Day 1 (p < 0.02). P-selectin expression increased from Day 5 to Day 7 (p < 0.04), whereas TRAP-6-inducible expression remained stable until Day 5 of storage and decreased significantly on Day 7 (p = 0.04).
Conclusions: Our results show that high-shear-induced PLT adhesion and aggregation on the polystyrene surface deteriorate upon storage, suggesting decreased PLT function in vivo. Thus, the Impact-R may be a useful tool to assess the functional capacity of PLTs under various PLT harvesting and storage procedures.