title: Extracellular vesicle characteristics in stored red blood cell concentrates are influenced by the method of detection.
abstract: Extracellular vesicles (EVs), including microvesicles and exosomes, are small phospholipid vesicles (≤1μm in diameter) that are present in blood products, accumulate during storage, and have a potential transfusion-related immunomodulatory role. Knowledge of EVs in stored blood products is limited due to the challenges and difficulties in detecting these heterogeneous submicron-sized vesicles. The aim of this study was to assess the impact of different approaches to characterize EVs in stored RBC products. Quantification and size-profiling of EVs in leukoreduced red cell concentrates (RCCs) were examined on day 3, 7, 21, and 42 of storage using tunable resistive plus sensing (TRPS), flow cytometer (FC), and dynamic light scatting (DLS) methods. Using the TRPS method, the concentration of EVs<200nm significantly increased throughout storage (p<0.05). This change in exosome concentration was not detectable with FC or DLS due to limitations in their ability to resolve particles <200nm and/or accurately determine EV concentration. Both the TRPS and FC demonstrate that the concentration of EVs≥200nm significantly increases in RCCs by day 42/43 compared to EVs present on day 3 (p<0.001). As the DLS measures the average size of particles in suspension, only an increase in the zeta-average size was observed during storage. EV size and concentration in RBC products is significantly influenced by the length of storage. Overall, this study shows that combining technologies may be important to improve the characterization and study of EVs in stored RCCs.
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada T6G 2R8.
authors.forename: Ruqayyah J
authors.initials: RJ
authors.lastname: Almizraq
authors.affiliation: International Consultancy in Blood Component Quality/Safety Improvement, Audit/Inspection and DDR Strategies, London, UK. Electronic address: jseghatchian@btopenworld.com.
authors.forename: Jerard
authors.initials: J
authors.lastname: Seghatchian
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada T6G 2R8; Centre for Innovation, Canadian Blood Services, Edmonton, Alberta, Canada T6G 2R8.
authors.forename: Jelena L
authors.initials: JL
authors.lastname: Holovati
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada T6G 2R8; Centre for Innovation, Canadian Blood Services, Edmonton, Alberta, Canada T6G 2R8. Electronic address: jason.acker@blood.ca.
authors.forename: Jason P
authors.initials: JP
authors.lastname: Acker
mesh_terms: D001793:Blood Preservation; D055252:Cell-Derived Microparticles / Q000378:metabolism*; D004912:Erythrocytes / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D013997:Time Factors
keywords: Blood bank; Erythrocyte; Exosomes; Microparticles; Transfusion medicine