A hemocompatible cryoprotectant inspired by freezing-tolerant plants

Area of Science:

• Biomedical Engineering
• Cell Biology
• Cryobiology

Background:

• Current red blood cell (RBC) preservation methods are limited to 42 days, leading to significant blood waste and shortages.
• Organic solvents like glycerol and DMSO used as cryoprotective agents (CPAs) cause severe RBC hemolysis during removal, hindering long-term cryopreservation.

Purpose of the Study:

• To develop a novel, hemocompatible method for cryopreserving RBCs using a natural, organic solvent-free cryoprotectant.
• To investigate the efficacy of betaine as a CPA for RBCs and elucidate its protective mechanisms against freeze-thaw injury.

Main Methods:

• An ultrarapid freezing protocol was employed for RBC cryopreservation using betaine.
• Post-thaw RBC integrity was assessed after cryopreservation and betaine removal.
• Mechanistic studies were conducted to understand betaine's role in inhibiting ice formation and preventing osmotic injury.

Main Results:

• Approximately 80% RBC integrity was achieved post-thaw using the betaine-based cryopreservation method.
• RBC integrity remained unaffected during betaine removal, demonstrating its hemocompatibility.
• Betaine was shown to inhibit ice formation and recrystallization, and likely facilitates prompt cellular uptake and release to prevent osmotic stress.

Conclusions:

• Betaine offers an effective and hemocompatible alternative to organic solvents for RBC cryopreservation.
• This natural zwitterionic compound provides a promising solution for long-distance and long-term RBC transport and storage.
• The betaine-based approach has the potential to significantly improve RBC transfusion support and reduce blood waste.