Ludmila B. Buravkova
Institute of Biomedical Problems RAS Russia
Title: Optimization of Cord Blood Stem/Progenitor Cells Expansion: Human Adipose-Tissue Derived Stromal Cells in Combination with Hypoxia Effectively Support Ex Vivo Multiplication of Hematopoietic Precursors
Biography
Biography: Ludmila B. Buravkova
Abstract
Cord blood hematopoietic stem/progenitor cells (cbHSPCs) attract considerable interest as an alternative to bone marrow HSPCs. Low number of HSPCs in one sample limit its broad application. Thus far, the development of ex vivo cbHSPC amplification is a primary goal of cell technologies. Imitation of hematopoietic niche ex vivo may significantly improve cbHSPC expansion. In this work, HSPCs were selected from unfractioned cbMNCs through adhesion to adipose mesenchymal stromal cells (ASCs) under standard (20%) and tissue-related (5%) О2. ASCs efficiently maintained viability and supported further HSPC expansion at both О2 levels. A new floating generation of HSPCs grew up and was enriched with СD34+cells up to 100 (20% О2) and 200 (5% О2) times, included cobble-stone area forming cells and colony-forming cells (CFCs). The number of CFCs was 1.6 times higher than at 20% О2 due to increase in multipotent precursors - BFU-E, CFU-GEMM and CFU-GM. These changes were at least partly ensured by increased of MCP-1 and IL-8 at 5% O2. After HSPC/aMSC interaction, up-regulation of cell adhesion molecule genes (ICAM-1,VCAM-1,CDH1) and down-regulation of matrix remodeling genes (COLs,MMPs,TIMPs,ADAMs,HAS1) were demonstrated by RT-PCR. This indicates on activation of ASC stromal function at 5% O2. Thus, the combination of cbMNCs and ASCs enables selection of HSPCs, whose further expansion without exogenous cytokines provides the CD34+cells enrichment. These data are important for elucidation of hematopoiesis mechanisms and as a tool for ex vivo HSPC expansion for the needs of regenerative medicine.