Characteristics of Extracellular Vesicles in Red Blood Concentrates Change with Storage Time and Blood Manufacturing Method

Abstract

Background: Extracellular vesicles (EVs) in blood products are potential effectors of inflammation and coagulation after transfusion. The aim of this study was to assess the impact of different blood manufacturing methods and duration of hypothermic storage on the EV subpopulations in relation to other in vitro quality parameters of red blood cell concentrate (RCC) products.

Methods: RCCs were produced using whole blood filtration (WBF) or red cell filtration (RCF) (n = 12/method), refrigerated for 43 days, and evaluated for EV size profile and concentration, red cell deformability, ATP and 2,3-DPG, hemolysis, and hematological indices.

Results: The total number of EVs increased significantly with storage in both methods, and WBF-RCCs contained the higher numbers of EVs compared to RCF-RCCs. The concentration of small EVs was greater in WBF-RCCs versus RCF-RCCs, with difference between the two methods observed on day 43 of storage (p = 0.001). Throughout storage, significant decreases were identified in ATP, 2,3-DPG, and EI_max, while an increase in hemolysis was observed in both RCC products.

Conclusion: The dynamic shift in the size and concentration of the EV subpopulations is dependent on the blood manufacturing method and length of storage. Better understanding of the potential clinical implications of these heterogeneous populations of EVs are needed.

Keywords: Blood processing; In vitro quality; Microparticles; Microvesicles; Red blood cells; Red cell filtered; Storage lesion; Whole blood filtered.

Fig. 1

Flow cytometer results shown the absolute number of CD235+ microparticles/μl (A), the percent RMP-PS (B), and MFI of PS (C) on RMPs in stored RCC products (RCF and WBF). Data are reported as mean ± 1 SD. *Significant results (p < 0.05) in comparison to day-7 values. (δ) Significant results (p < 0.05) in comparison to WBF method.

Fig. 2

Representative concentration (#/ml) versus size (nm) histograms of extracellular vesicles in hypothermically stored RCCs (A WBF and B RCF) up to 43 days as measured by the TRPS.

Fig. 3

Concentration of EVs/ml in RCC products stored for up to 43 days analyzed by the TRPS system; A EVs < 200 nm using NP200, B EVs ≥ 200 nm using NP400, and C total EVs using NP200 and NP400. Data are reported as mean ± SD. Significant results (p < 0.05) in comparison to day-8 values (*) or in comparison to B2 method (δ).

Fig. 4

Relationship between the total concentrations of EVs (EVs/ml) using TRPS and; (A), ATP, (B) Elmax, (C) % hemolysis of stored RCCs (RCF and WBF method).