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Successful short-term cryopreservation of volume-reduced cord blood units in a cryogenic mechanical freezer: effects on cell recovery, viability, and clonogenic potential

Authors

  • Ioannis Anagnostakis,

    1. Hellenic Cord Blood Bank, Foundation for Biomedical Research, Academy of Athens
    2. Department of Immunology and National Tissue Typing Center, “G. Gennimatas” General Hospital
    3. Department of Microbiology, Medical School, University of Athens, Athens, Greece
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  • Andreas C. Papassavas,

    1. Hellenic Cord Blood Bank, Foundation for Biomedical Research, Academy of Athens
    2. Department of Immunology and National Tissue Typing Center, “G. Gennimatas” General Hospital
    3. Department of Microbiology, Medical School, University of Athens, Athens, Greece
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  • Efstathios Michalopoulos,

    Corresponding author
    1. Hellenic Cord Blood Bank, Foundation for Biomedical Research, Academy of Athens
    2. Department of Immunology and National Tissue Typing Center, “G. Gennimatas” General Hospital
    3. Department of Microbiology, Medical School, University of Athens, Athens, Greece
    • Address reprint requests to: Efstathios Michalopoulos, PhD, Hellenic Cord Blood Bank (HCBB), Foundation for Biomedical Research, Academy of Athens, 4 Sorranou Efessiou Street, 11527 Athens, Greece; e-mail: smichal@bioacademy.gr.

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  • Theofanis Chatzistamatiou,

    1. Hellenic Cord Blood Bank, Foundation for Biomedical Research, Academy of Athens
    2. Department of Immunology and National Tissue Typing Center, “G. Gennimatas” General Hospital
    3. Department of Microbiology, Medical School, University of Athens, Athens, Greece
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  • Sofia Andriopoulou,

    1. Hellenic Cord Blood Bank, Foundation for Biomedical Research, Academy of Athens
    2. Department of Immunology and National Tissue Typing Center, “G. Gennimatas” General Hospital
    3. Department of Microbiology, Medical School, University of Athens, Athens, Greece
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  • Athanassios Tsakris,

    1. Hellenic Cord Blood Bank, Foundation for Biomedical Research, Academy of Athens
    2. Department of Immunology and National Tissue Typing Center, “G. Gennimatas” General Hospital
    3. Department of Microbiology, Medical School, University of Athens, Athens, Greece
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  • Catherine Stavropoulos-Giokas

    1. Hellenic Cord Blood Bank, Foundation for Biomedical Research, Academy of Athens
    2. Department of Immunology and National Tissue Typing Center, “G. Gennimatas” General Hospital
    3. Department of Microbiology, Medical School, University of Athens, Athens, Greece
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Abstract

Background

Cord blood (CB) units are stored from weeks to years in liquid- or vapor-phase nitrogen until they are used for transplantation. We examined the effects of cryostorage in a mechanical freezer at −150°C on critical quality control variables of CB collections to investigate the possible use of mechanical freezers at −150°C as an alternative to storage in liquid- (or vapor-) phase nitrogen.

Study Design and Methods

A total of 105 CB 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 (total nucleated cells [TNCs], mononuclear cells [MNCs], CD34+, CD133+) was performed. In addition, viability was obtained with the use of flow cytometry, and recoveries were calculated. Also, total absolute colony-forming unit counts were performed and progenitor cell recoveries were studied by clonogenic assays.

Results

Significant differences (p < 0.05) were observed in certain variables (TNCs, MNC numbers, viability) when they were examined in relation with time intervals, 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 in a mechanical freezer at −150°C may represent an alternative cryostorage condition for CB cryopreservation.

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