Summary:
BACKGROUND: Cord blood (CB) units are stored from weeks to years in liquid or
vapour phase nitrogen until they are used for transplantation.We examined the
effects of cryostorage in a mechanical freezer at -1500C on critical quality
control variables of CB collections and to investigate the possible use of
mechanical freezers at -1500C as an alternative to storage in liquid (or
vapour) phase nitrogen.
STUDY DESIGN AND METHODS: One-hundred and five cord blood units were thawed
and washed at different time intervals (6, 12, 24 and 36 months). For every
thawed CB unit, samples were removed and cell enumeration was performed. In
addition, viability was obtained with the use of flow cytometry and recoveries
were calculated.Also, clonogenic assays were performed.
RESULTS: Significant differences (p<0.05) were observed in certain variables
(TNC, MNC numbers, viability), while others (CD34+, CD133+ ) were relatively
insensitive (p=NS) to the duration of time interval the CB units were kept in
cryostorage condition.
CONCLUSIONS: The data presented suggest that cryopreservation of CB units has
little if no influence on the extensive proliferative capacity of the
hematopoietic progenitor cells of the CB and that mechanical freezers at -1500C
may represent an alternative cryostorage condition for CB cryopreservation.
Keywords:
Cryopreservation, Cord blood, Mechanical freezers, Hematopoietic stem cells, Cord blood banks
