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I. Marini et al.
exposure of desialylated GPs in PLTs stored at different plasma concentrations. In the lectin binding assay (LBA), neither storage temperature nor plasma content had a major effect on β-galactose expression (Figure 2A and B). Only PLTs from PAS-35-APCs stored for seven days at 4°C showed a slightly higher exposure of β-galactose on their surface compared to those stored at RT.
In contrast, higher exposure of phosphatidylserine was
always detected on the surface of cold-stored PLTs (per- centage of Annexin V positive events mean±SEM: PAS-35- APC 9±1 vs. 7±1, respectively, P=0.033; Figure 2C; PAS- 20-APC 22±4 vs. 17±5, respectively, P=0.317; Figure 2D). The cold-induced increase in the exposure of phos- phatidylserine was not correlated to the residual plasma concentration indicating that cold storage of APCs affects PLT survival by inducing cell apoptosis in a plasma-inde-
A
BC
DE
Figure 3. Platelet adhesion to collagen and fibrinogen after storage at room temperature (RT) or 4°C. (A) Representative images of adherent platelets (PLTs) from different apheresis platelet concentrates (APCs) after seven days of storage (scale bar 10 mm). PLTs from APCs containing 100% plasma (Plasma-APC), 35% plasma (PAS-35-APC) and 20% plasma (PAS-20-APC) were allowed to adhere to collagen (B and C) or fibrinogen (D and E) surfaces in the presence of TRAP. The number and types of adherent PLTs were determined from 5 different microscopic fields per coverslip (see Online Supplementary Figure S2 and Online Supplementary Table S1A and B for further details). Freshly isolated PLTs were used as positive control (100%). Data are shown as mean±Standard Error of Mean. *P<0.05. ns: not sig- nificant (n=3).
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haematologica | 2019; 104(1)