[Erythrocytes after cryopreservation with HES: molecular, structural and functional characteristics]

Cryopreservation of erythrocytes is a critical process in blood banking and transfusion medicine. While glycerol has traditionally been used as a cryoprotectant, it has limitations such as toxicity and lengthy thawing protocols. Prior research has shown that hydroxyethylstarch (HES) can serve as a viable alternative. However, the molecular and functional impacts of HES-based cryopreservation on erythrocytes remain understudied. This gap motivated the current investigation. No prior work had resolved whether HES-preserved erythrocytes maintain structural and metabolic integrity after thawing. Understanding this is essential for broader clinical adoption. The study aimed to address these uncertainties. It evaluated post-thaw erythrocyte behavior in both in vitro and in vivo settings. This approach helps determine the practicality of HES as a cryoprotectant.

The purpose of this study was to assess the molecular, structural, and functional characteristics of erythrocytes after cryopreservation using HES. The researchers aimed to determine whether HES-preserved erythrocytes retain their normal morphology and function after thawing. They also sought to evaluate the metabolic stability and oxygen-carrying capacity of these cells. This investigation is crucial for validating HES as a safe and effective cryoprotectant. The study focused on both in vitro and in vivo models to ensure comprehensive evaluation. They used intravital microscopy to observe erythrocyte distribution in capillaries. The researchers also measured post-thaw hemolysis and survival rates in dogs. These assessments help determine the clinical viability of HES-preserved erythrocytes.

The researchers used hydroxyethylstarch as a cryoprotectant for erythrocytes. They compared the effects of HES with those of traditional cryopreservation methods. Immediately after thawing, they analyzed membrane rigidity and skeletal structure. Intravital microscopy was used to track erythrocyte distribution in the dog's mesentery. They measured ATP levels and the activity of the GluT 1 glucose transporter. The O2-association and dissociation functions were evaluated using hemoglobin saturation curves. Free radical oxygen species were quantified to assess oxidative stress. Post-thaw hemolysis and 24-hour survival rates were determined in both human and canine models.

Erythrocytes thawed with HES showed initial membrane rigidity changes and altered morphology. These changes reverted to normocytotic forms within minutes of resuspension. Intravital microscopy showed even erythrocyte distribution in the capillary bed. ATP levels were reduced by 20–40%, but the turnover rate remained unchanged. Glucose transport via GluT 1 was unaffected, ensuring metabolic stability. Hemoglobin oxygen saturation was normal despite a rightward shift in O2-association. Free radicals from freezing were neutralized by the erythrocyte's antioxidant system. Post-thaw survival in dogs was 95%, with no significant hemolysis in human cells.

The study concluded that HES cryopreservation preserves erythrocyte function and viability. The observed ATP reduction was not harmful due to stable turnover and glucose transport. Oxygen-carrying capacity remained intact despite a rightward O2 shift. Free radicals were effectively neutralized by the erythrocyte's antioxidant defenses. Post-thaw survival rates in dogs were high, with minimal hemolysis in human cells. These findings support the clinical potential of HES as a cryoprotectant. The authors propose that HES could replace glycerol in cryopreservation protocols. They suggest that this method may reduce infectious risks and improve blood supply logistics.