Variation in the quality of stored red cell concentrates (RCCs) has been linked to the biological age distribution of red blood cell (RBCs) subpopulations within blood products. Teen male RCCs contain higher proportions of biologically old RBC subpopulations, with poorer quality. This study sought to assess the contribution of donor sex and age on the deformability characteristics of different ages of RBC subpopulations in stored RCCs. On days 5, 14, 21, and 42 of hypothermic storage, RCCs from healthy teen male, senior male, teen female and senior female donors were biologically age profiled. The deformability of the resulting young (Y-RBCs) and old (O-RBCs) RBC subpopulations in addition to unseparated RBCs was assessed using ektacytometry. Over storage, donor age influenced the rheological profile of RBC subpopulations, with teen male RCCs having the largest reduction in Ohyper (the osmolality in the hypertonic region corresponding to 50% of the EImax). The strongest correlations between Ohyper and MCHC (R2 > 0.5) were witnessed with O-RBCs from senior donors, and to a lesser extent with teen males. O-RBCs from teens, particularly males, had higher elongation indices both under isotonic conditions and in the presence of an increasing osmotic gradient. Consistent across RBCs regardless of their biological age, teen samples were discovered to be more rigid (higher KEI). The donor-to-donor variation in age distribution of RBC subpopulations and its downstream effect on deformability serves as further evidence that factors beyond chronological aging could potentially impact the quality of red cell concentrates and variations in transfusion outcomes.
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