EFFECT OF STROMAL CELLS AND OXYGEN CONCENTRATION ON THE MAINTENANCE OF CORD BLOOD HEMATOPOIETIC PRECURSORS
The paper analyses the morphological and functional features of cord blood cells (CBCs) in the co-culture with multipotent mesenchymal stromal cells (MMSCs) from human adipose tissue under tissue-related oxygen. We have established that MMSCs effectively maintained viability of CBCs at different oxygen concentrations (1, 5 and 20 %). According to the data obtained, the oxygen concentration affected the number of colony-forming units (CFUs) formed by CBCs in selective medium. In particular, not co-cultured CBCs the 1 and 5% O <sub>2</sub> than at 20 % O <sub>2</sub>. After co-culture with MMSCs, the CFUs numbers were similar at 1 and 20 % O <sub>2</sub> and increased by 30 at 5% O <sub>2</sub>. Tissue related O <sub>2</sub> concentrations had an impact on the proportion of lineage-resctricted CFCs among CBCs: the number of more committed progenitors - CFU-G and CFU-M, increased, and multi and bipotent - CFU-GEMM and CFU-GM, decreased at low oxygen concentrations. This effect was more pronounced after co-culture compared to that of initial CBCs. Thus, the presence of stromal cells and tissue-related oxygen jointly and severally influenced CBCs in vitro.