High Integrity and Fidelity of Long-Term Cryopreserved Umbilical Cord Blood for Transplantation

Abstract

Umbilical cord blood (UCB) is used as a source of donor cells for hematopoietic stem cell (HSC) transplantation. The success of transplantation is dependent on the quality of cord blood (CB) units for maximizing the chance of engraftment. Improved outcomes following transplantation are associated with certain factors of cryopreserved CB units: total volume and total nucleated cell (TNC) count, mononuclear cell (MNC) count, and CD34+ cell count. The role of the storage period of CB units in determining the viability and counts of cells is less clear and is related to the quality of cryopreserved CB units. Herein, we demonstrate the recovery of viable TNCs and CD34+ cells, as well as the MNC viability in 20-year-old cryopreserved CB units in a CB bank (MEDIPOST Co., Ltd., Seongnam-si, Gyeonggi-do, Korea). In addition, cell populations in CB units were evaluated for future clinical applications. The stable recovery rate of the viability of cryopreserved CB that had been stored for up to 20 years suggested the possibility of uses of the long-term cryopreservation of CB units. Similar relationships were observed in the recovery of TNCs and CD34+ cells in units of cryopreserved and fresh CB. The high-viability recovery of long-term cryopreserved CB suggests that successful hematopoietic stem cell (HSC) transplantation and other clinical applications, which are suitable for treating incurable diseases, may be performed regardless of long-term storage.

The fulfilled promise and unmet potential of umbilical cord blood

“…Indeed, a retrospective single center study supported this idea by showing similar levels of predicted potency for CBU stored for 29 years compared to CBU used successfully in patient transplantations [28]. These findings, among other CB stability studies [29][30][31][32] suggest that age of the unit by itself is not an effective exclusionary criterion for CBU selection for hematopoietic transplant for CD34 driven hematopoietic reconstitution.…”

Banking of AT-MSC and its Influence on Their Application to Clinical Procedures

“…In accord with this the viability of our AT-MSCs ranged from 78 to 90% although we stored the cells markedly shorter. On the other hand, it was demonstrated that long-term storage of hematopoietic cells at −150°C did not affect the cells’ viability proliferative potential ( Broxmeyer et al, 2003 ; Broxmeyer et al, 2011 ; Kim et al, 2021 ). Some authors ( Oja et al, 2019 ) demonstrated a better than our viability of the frozen-thawed cells, but only in cells obtained from the first passages.…”

A comprehensive report of long-term stability data for a range ATMPs: A need to develop guidelines for safe and harmonized stability studies

“…The data presented are not surprising, since many other cell products or tissues are known to maintain high viability and functionality for extended times when resuspended in iso-osmotic solutions containing 10% DMSO and cryopreserved in nitrogen vapor [50À53]. Successful long-term storage of cell-based medicines for therapeutic transplantation has been extensively demonstrated over many years, for example, hematopoietic stem cells used in the context of hematopoietic transplantation, which can be conserved in a cryopreserved state for 20 years [54,55]. Human embryos stored at <À150°C for 12 years have been shown to be fully viable and implant successfully in utero, giving rise to healthy babies [56,57].…”