Microparticles in stored canine RBC concentrates

Background Transfusion of RBC concentrates may cause adverse effects in the recipient, particularly when stored > 2 weeks. Prestorage removal of WBCs and platelets (leukoreduction, LR) improves clinical outcome in the human recipient. As blood ages during storage, progressive alterations in the structure and function of the cells occur. Changes in cell membranes may lead to formation of microparticles (MPs) in stored blood. Objectives The aim of the study was to quantify MP concentration in supernatants from canine RBC concentrates from 11 clinically healthy dogs. Methods Whole blood units (n = 11) were collected and randomized either to be stored without LR (n = 5), or to be subject to prestorage LR (n = 6). Whole blood was processed for the generation of RBC concentrates, from which aliquots were aseptically collected weekly for 5 weeks. Supernatants from the concentrates were evaluated for phosphatidylserine-expressing MPs by flow cytometry using staining with Annexin-V-phycoerythrin. Results Microparticle counts were similar between non-LR and LR units on storage days 0 and 7, but were significantly higher in non-LR units on days 14, 21, 28, and 35. MPs increased during the 35-day storage by a mean (SD) of 1.8 (1.4)-fold in LR units and 5.5 (3.1)-fold in non-LR units. Conclusions There was marked formation of phosphatidylserine-expressing MPs during storage beyond 7 days in canine RBC concentrates. Prestorage LR attenuated the generation of MPs.