Razi Journal of Medical Sciences

Background: Umbilical cord blood has been increasingly used as an alternate source of hematopoietic stem cells in the treatment of Hematologic malignancies and life-threatening diseases. The success of engraftment and survival of patients after cord blood transplantation highly depend on either the number of infused total nucleated cells (TNCs) or the number of CD34+ cells per kilogram of recipient body weight. A standardization procedure for cord blood (CB) storage before and during cryopreservation is critical. This work is concerned with the effect of CB storage temperature and storage duration through the stages before cryopreservation on cell recovery, viability, aggregation of cells.

Methods: Total of 30 CB samples were casual collected from Tehran hospitals and remittances to cord blood bank. Total cells and viability were calculated and aggregation was evaluated. Each sample divided to 4 sample and stored at 4ᵒC, 12 ᵒC, 22 ᵒC, and 37 ᵒC for different periods of time after 12, 24, 48 and 72 hours. Total cells and viability were calculated and aggregation was evaluated. Subsequently, these results were evaluated with ANOVA methods.

Results: At the beginning of the experiment, the total number of cells was 5-10 million/ml. All the specimens were investigated after 24 hours. At 4 cº a decrease in the number of viability cells was observed that was statistically significant with a p<0.005. However, the reduction in the number of live cells at 12 degrees Celsius and 24 degrees Celsius was not statistically significant (p>0.005). A significant drop (p<0.005) in the number of live cells was observed at 37 cº.

Conclusion: This study shows that the vulnerability level of cells outside the body from cord blood collection till separation and freezing is directly correlated with storage time and temperature, which is statistically significant with a p<0.005. Nevertheless, changing temperature and storage time did not affect aggregation of cells. These findings suggest that the optimum temperature for storing cord blood is 12-22 cº degrees Celsius for up to 48 hour