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

Gee-Hye Kim,Hye Kyung Hong,Hye Jin Jin,Sung Hee Kim,Hee Jung Kim,Soyoun Um,Jihye Kwak,Soo Jin Choi,Wonil Oh

doi:10.3390/jcm10020293

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.

Highlights

Cell therapy, which plays a central role in regenerative medicine, involves the application of viable cells for treating or curing medical conditions or diseases
The results show that the viability of mononuclear cells (MNCs) remained unaffected by the storage period (Figure 2A), as indicated by the levels of apoptosis determined using Annexin V/propidium iodide double staining performed using MNCs isolated from cryopreserved cord blood (CB) units (2000, 2005, and 2010) and fresh CB units
CB has been used as a source of hematopoietic stem and progenitor cells in over 40,000 clinical hematopoietic cell transplantations to treat hematological, metabolic, immunological, neoplastic, and neurological disorders

Summary

Introduction

Cell therapy, which plays a central role in regenerative medicine, involves the application of viable cells for treating or curing medical conditions or diseases. We evaluated whether CB banking helps retain the viability of cryopreserved cells stored for up to 20 years. To determine the stability of TNCs, the viable cells were analyzed after processing and before cryopreservation. For the evaluation of long-term storage stability, three sets of CB units were analyzed. The segments attached to the freezing bags for the 116 CB units were used to assess the viability and TNC cell count recovery before transplantation. For assessing the long-term storage stability, the viability, TNC count, and CD34+ cells count were evaluated every year for 1–10 years. An Annexin V-FITC early apoptosis detection kit (Cell Signaling, Boston, MA, USA) was used to evaluate cell viability and detect apoptosis according to the suggested protocol. A p < 0.05 was considered to represent a statistically significant difference

Results

Comparison of MNC Viability in Cryopreserved and Fresh UCB

Characteristics of Store CB Units Used for Transplantation

Discussion