Mechanical Fragility as a Potential Time-Independent Measure of Membrane Integrity among Stored RBC Units

Abstract

Background and Objectives: Previous studies have shown that storage causes RBC membrane damage and subsequent potassium leakage to extracellular environment, with the effects exacerbated by RBC irradiation. While damage to RBC appears to worsen with storage time (ST), ST alone has not been shown to fully account for this phenomenon. It is therefore important to study the extent to which other time-independent factors can affect RBC membrane integrity. RBC mechanical fragility (MF) is evaluated as a surrogate measure of RBC membrane integrity due to its potential to reflect aggregate biochemical and biomechanical changes associated with storage. Materials and methods: Samples from 45 units non-irradiated and 58 units of irradiated leuko reduced RBC units were subjected to shear stress using a bead mill at different durations at a fixed intensity (50 Hz); induced hemolysis was ascertained via spectral analysis. Profile curves characterized the relationship between stress duration and induced hemolysis, from which specific parameter values were interpolated. Results: There was high variability among RBC MF parameters. MF profiles were significantly variable among both irradiated and non-irradiated stored RBC units, and in some, within the same units which resulted in distinguishable subpopulations. RBC base-line hemolysis (hemolysis before stress application) MF variation was largely independent of ST. Donor blood type appeared to influence MF parameters and base-line levels. Conclusion: RBC membrane properties, as defined by MF, vary markedly across RBC units. This variability is largely independent of ST. MF could potentially be used clinically to assess RBC membrane.