Corresponding author: Max Hansen, Vita 34 AG, Deutscher Platz 5a, 04103 Leipzig, Germany. Tel.: +49 341 48792886; E-mail: [email protected].
Abstract: BACKGROUND:The umbilical cord contains stem and progenitor cells in vast amounts. Therefore, a long-term storage of this tissue for future therapies seems reasonable. OBJECTIVE:The aim of this study was a systematic comparison of mesenchymal stromal cells from fresh and cryopreserved umbilical cord tissue to demonstrate the feasibility of cryopreservation of tissues for later cell isolation. Furthermore, we tested the cultivation of these cells in GMP-compliant human AB serum, as a substitute for FCS, and subjected the expanded cells to karyotype analysis. METHODS:We applied limiting dilution analysis for evaluation of fibroblastoid colony-forming units and flow cytometric analysis of surface markers. Additionally we analyzed adipogenic and osteogenic differentiation potential. RESULTS:High numbers of viable MSC were isolated from cryopreserved umbilical cord tissue and a proportion of these cells showed clonal proliferation. The cells expressed the classic mesenchymal stromal cell surface markers, and effectively differentiated into osteocytes and adipocytes. Culture expansion of the mesenchymal stromal cells in medium supplemented with human AB serum did not change the surface marker profile. Moreover, karyotype analysis revealed genetic stability of mesenchymal stromal cells during expansion. CONCLUSIONS:Cryopreservation of umbilical cord tissue represents an auspicious approach for long-term storage of umbilical cord tissue and therefore a valuable tool for autologous stem cell applications.