Impact of storage temperature and processing delays on cord blood quality: discrepancy between functional in vitro and in vivo assays

Abstract

Background: Optimal conditions of cord blood (CB) storage, processing, cryopreservation, and thawing are critical for banking and transplantation. Nevertheless, standardized procedures are still awaited.

Study design and methods: We evaluated the impact of preprocessing storage and temperature on recovery, viability, and functional differentiation capacities of hematopoietic progenitor cells. We compared units stored at room temperature (RT) or at 4 °C for 72 hours before cryopreservation to units processed shortly after collection (<12 hr).

Results: Postthaw results showed similar in vitro characteristics between immediate processing and 4 °C storage for cell recovery and viability, both significantly higher than RT storage. Surprisingly, we demonstrated that storage of CB units at RT before processing and cryopreservation profoundly altered in vivo hematopoietic reconstitution in mice, although in vitro hematopoietic colony-forming unit potential was unaltered.

Conclusion: Our findings challenge current CB storage practices and suggest standard in vitro quality assessments may not always be indicative of CB engraftment potential.