GPVI-dependent functional competence of buffy coat platelet concentrates (PCs) versus PRP-derived PCs: insights into the effects of biomechanical forces during platelet preparation.

Platelet isolation is a decisive stage in the preparation of platelet concentrate (PC), which may affect functional competence of platelets during storage and post-transfusion. Now considering GPVI as a vulnerable receptor that is mainly affected by shear stress and redox state, this study was conducted for the first time to compare preparation methods of Buffy Coat (BC)- and Platelet-Rich Plasma (PRP)-PCs in terms of GPVI-related phenotypic and functional status. BC- and PRP-PCs were subjected to flow cytometry to analyze GPVI expression and intra-platelet ROS generation. Soluble GPVI were determined by ELISA. Platelet aggregation response to collagen and its adhesion to the collagen matrix were examined by aggregometry and fluorescence microscope, respectively. All the parameters were analyzed on days 0, 1, 3, and 5 of storage. Stored-dependent ROS generation showed significantly higher levels in PRP-PCs compared to BC-PCs on days 1 and 3 of storage. GPVI expression decreased in both products, with BC-PCs showing higher levels on 1 and 3 days of storage. However, with a similar trend, PRP-PCs showed higher levels of shedding, which was significant on day 3. Adhesion/spreading to the collagen matrix also decreased during storage, with higher declines observed in PRP-PCs. Platelet aggregation showed the same pattern with significantly lower PRP-PCs responses to collagen than BC-PCs on the third and fifth days of storage. During platelet storage, GPVI-dependent platelet functional capacity in BC-PCs was better preserved than PRP-PCs, suggesting the priority of BC-PCs method for platelet preparation. In this regard, adopting methods such as platelet isolation and storage in optimal additive solutions, especially those containing ROS scavengers, may help maintain the integrity of GPVI in PRP products. However, further studies, particularly using animal models of thrombus formation, are needed to determine whether the enhanced GPVI function in BC-PCs compared with PRP-PCs can translate into superior efficacy after blood transfusion.