Hematopoietic Progenitor Content of Fetal Cord Blood Collected Using Citrate-Phosphate-Dextrose: Influence of Holding Temperature and Delays

Abstract

Storage of unseparated fetal cord blood collected into citrate-phosphate-dextrose (CPD) for 48 hours has been studied using progenitor cell assays [plasma clot technique with plasma-conditioned medium, erythropoietin (EPO), erythropoietin + IL-3 as growth factors]; collected fetal blood volume was low [61 +/- 4 ml, mean +/- 95% confidence interval (CI)]. The CFU-GM concentration in total cord blood was 2460 +/- 1476 CFU-GM/ml, comparable to normal bone marrow collected into medium RPMI + heparin (2350 +/- 1258); 2 of 12 samples contained fewer than 10(3) CFU-GM. Storage of unseparated cord blood CFU-GM in CPD was better at 4 degrees C (rapid decrease at day (D) 2 from 15 +/- 9 x 10(4) at D0; 14 +/- 11 x 10(4) at D1 to 6 +/- 4 x 10(4) at (D2) than at 22 degrees C (strong decrease since D1: 5 +/- 4 x 10(4) CFU-GM). The CFU-GEMM content remained steady at 4 degrees C: from 16 +/- 16 x 10(4) at D0 to 18 +/- 16 at D2. Cryopreservation and thawing of unfractionated cord blood at D0 did not affect the CFU-FM cloning rates. Whether mature progenitors are more affected than stem cells by storage in CPD remains to be determined.

Short‐term liquid storage of umbilical cord blood

“…Similar results were observed by Broxmeyer et al 34 who observed little difference in the colony formation from cord blood stored for up to 3 days at both 4°C and RT. This result differs from a study by Tron de Bouchony et al 35 in which colony formation for cord blood was improved for cord blood stored at 4°C for up to 48 hours. As with nucleated cell counts and CD34+ recovery, there was little variation in CFU‐GM per 10 5 cells measured.…”

Avoiding room temperature storage and delayed cryopreservation provide better postthaw potency in hematopoietic progenitor cell grafts

“…CB units are routinely frozen and banked before transplantation; these data suggest that units should be maintained at refrigerated temperatures and cryopreserved as soon after collection as possible (preferably within the first 24 hr but no later than 48 hr) to retain the highest possible potency of the cells. This range is in support of the current recommendations of NetCord‐FACT standards and in agreement with other studies . The PBSC results confirm earlier reports that the viability of the cells within samples are maintained best when stored at refrigerated temperatures .…”

“…Worryingly it has also been reported that PBSC and BM products with an increased transport time can lead to slower platelet (PLT) engraftment, suggesting a potential impact of the conservation conditions on the transplantation outcomes. Optimal fresh storage conditions have not as yet been established and the current literature remains inconclusive; according to current literature CB, PBSCs, and BM all have optimal storage temperatures of either refrigerated temperature (4‐8°C [4°C]) or 25°C depending on which group conducted the study and over what time period …”

Factors which can influence the quality related to cell viability of the umbilical cord blood units

“…Thus, the storage temperature of UCB units from collection to cryopreservation seems to be an essential factor that influences the cell viability and contributes to maintaining the final product quality. The controversial results show that UCB units must be stored before processing at 4°C [4][5][6][7] or at room temperature [8][9][10]. Other authors consider that there are no differences reflected in the quality of transplant units depending on the storage temperature [11][12][13].…”