Background: Ex vivo cold storage of red blood cells (RBCs) for transfusion has long been associated with hypothermic storage lesions. It has been proposed that liposomes can be used to mitigate hemorheological elements of RBC membrane storage lesions. This study aimed to determine the appropriate liposome treatment time and assess the effects of liposome treatment on RBC's hemorheological and metabolic profiles.
Materials and methods: Unilamellar liposomes were synthesized to contain a bilayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC):cholesterol (7:3 mol%). Packed human RBCs (n = 4) were divided into untreated control (HEPES-NaCl solution) and liposome-treated samples (2 mM DOPC liposomes) and treated at days 2, 21, and 42 of hypothermic storage. RBC quality assessment included percent hemolysis, deformability, aggregation, hematological indices, microvesiculation, supernatant potassium, adenosine triphosphate (ATP), and 2,3-diphosphoglycerate (2,3-DPG).
Results: Among the parameters affected by liposome treatment time were deformability, aggregation amplitude (Amp), mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and microparticle mean fluorescence intensity. After 6 weeks of storage, aggregation index (AI) and Amp were significantly increased in liposome-treated RBCs (AI: 45.38 ± 1.92% vs. 41.54 ± 4.10%, p = 0.020; Amp: 16.38 ± 2.17 arbitrary units [au] vs. 12.22 ± 3.29 au, p = 0.019). Despite comparable hemolysis levels at 3 and 6 weeks, DOPC-treated RBCs showed significantly increased potassium levels for the same time points (3 weeks: 31.2 ± 2.7 mmol/L vs. 30.8 ± 2.7 mmol/L, p = 0.007; 6 weeks: 45.0 ± 3.0 mmol/L vs. 43.8 ± 3.4 mmol/L, p = 0.013). ATP and 2,3-DPG levels were comparable throughout storage.
Conclusions: Liposome treatment seemed to be more beneficial when performed at the beginning of storage up to day 21. DOPC liposome treatment resulted in an improvement in human RBC hemorheology upon storage, with no significant impact on metabolic profile.
Keywords: biopreservation; blood banking; liposomes; red blood cells.