Characterization of Platelet Protein Alterations in Stored Platelet Concentrates

Background: Platelet concentrates (PCs) are vital for treating hematologic disorders and thrombocytopenia, yet their short shelf life (3–5 days) is limited by platelet storage lesion (PSL)—a process involving biochemical and structural deterioration that reduces post-transfusion efficacy. This study aimed to characterize alterations in platelet surface receptors and RNA content during storage to better understand PSL mechanisms. Methods: Platelet-rich plasma (PRP) and platelet-poor plasma (PPP) were prepared from healthy donors and stored PCs. Flow cytometry was used to assess the expression of GPIbα, GPVI, Integrin αIIbβ3, and CD9. Thiazole orange (TO) staining evaluated RNA content to distinguish young from aged platelets, while soluble GPVI (sGPVI) levels were quantified by ELISA. Data were analyzed using one-way ANOVA and Student’s t-test (p < 0.05). Results: Baseline receptor profiles were established from fresh donor platelets. Stored PCs showed a progressive decline in GPIbα and GPVI expression from day 6, with significant reductions by day 11 (p < 0.05). αIIbβ3 expression decreased early (day 6) and stabilized thereafter, whereas CD9 remained unchanged. TO staining indicated a gradual loss of RNA-rich platelets, signifying aging. ELISA revealed increased sGPVI levels from day 6 to day 14, inversely correlating with surface GPVI loss. Conclusions: Prolonged storage leads to receptor degradation and platelet senescence, notably affecting GPIbα, GPVI, and αIIbβ3. Elevated sGPVI levels and reduced RNA content reflect progressive PSL. Flow cytometry and ELISA offer reliable monitoring tools, and sGPVI may serve as a biomarker for platelet quality during storage.