Comparing two extracellular additives to facilitate extended storage of red blood cells in a supercooled state

Abstract

Background: Adenosine triphosphate (ATP) levels guide many aspects of the red blood cell (RBC) hypothermic storage lesions. As a result, efforts to improve the quality of hypothermic-stored red cell concentrates (RCCs) have largely centered around designing storage solutions to promote ATP retention. Considering reduced temperatures alone would diminish metabolism, and thereby enhance ATP retention, we evaluated: (a) whether the quality of stored blood is improved at −4°C relative to conventional 4°C storage, and (b) whether the addition of trehalose and PEG400 can enhance these improvements.Study Design and Methods: Ten CPD/SAGM leukoreduced RCCs were pooled, split, and resuspended in a next-generation storage solution (i.e., PAG3M) supplemented with 0–165 mM of trehalose or 0–165 mM of PEG400. In a separate subset of samples, mannitol was removed at equimolar concentrations to achieve a fixed osmolarity between the additive and non-additive groups. All samples were stored at both 4°C and −4°C under a layer of paraffin oil to prevent ice formation.Results: PEG400 reduced hemolysis and increased deformability in −4°C-stored samples when used at a concentration of 110 mM. Reduced temperatures did indeed enhance ATP retention; however, in the absence of an additive, the characteristic storage-dependent decline in deformability and increase in hemolysis was exacerbated. The addition of trehalose enhanced this decline in deformability and hemolysis at −4°C; although, this was marginally alleviated by the osmolarity-adjustments. In contrast, outcomes with PEG400 were worsened by these osmolarity adjustments, but at no concentration, in the absence of these adjustments, was damage greater than the control.Discussion: Supercooled temperatures can allow for improved ATP retention; however, this does not translate into improved storage success. Additional work is necessary to further elucidate the mechanism of injury that progresses at these temperatures such that storage solutions can be designed which allow RBCs to benefit from this diminished rate of metabolic deterioration. The present study suggests that PEG400 could be an ideal component in these solutions.

Extended supercooled storage of red blood cells

“…Hypothermic storage in all the solutions resulted in ∼ 1% hemolysis, except UW+Tre, which caused ~ 12% hemolysis and was eliminated from further testing. PAG3M was also eliminated due to its poor performance at −5 °C relative to +4 °C beyond 6 weeks 52 .…”

“…In that study, AS-3 and UW solutions were used for RBC suspension. In a recent follow-up study, we investigated whether the quality of stored RBCs was improved at −4 °C relative to +4 °C in the next-generation PAG3M solution in the presence of two extracellular additives: trehalose and polyethylene glycol (PEG) 52 . Despite the improvements with PEG addition into the PAG3M formulation, the samples stored in PAG3M showed much higher hemolysis levels at −4 °C compared to +4 °C beyond 6 weeks of storage.…”

Supercooling: a promising technique for prolonged preservation in solid organ transplantation, and early perspectives in vascularized composite allografts

“…As for extracellular CPAs, needed to prevent the intravascular compartment and the surrounding media from freezing, most of the preservation protocols in solid organs have been using polyols and polyethers such as glycerol and polyethylene glycol (PEG) ( 86 – 41 ). Nature-inspired molecules like Trehalose, a complex sugar used by plants to avoid freezing, have also been experimented with ( 88 , 89 ). Different protocols were tested for various organs, involving diverse processes.…”

Reply to Kaestner et al.: Pioneering quantitative platforms for stored red blood cell assessment open the door for precision transfusion medicine

“…Until these efforts evolve and find their way into the transfusion workflow and infrastructure, relatively easier steps can be taken. For example, more of the eligible population can be motivated to donate to address recurrent blood shortages; alternative storage practices can be considered to address blood wastage and storage lesions ( 9 ); and quantitative assessment of RBC quality can be performed to address the ethical dilemma and clinical consequences of donor-to-recipient selection.…”