RESUMEN
PURPOSE: Umbilical cord blood transplantation is a alternative method as new hematopoietic stem cell transplantation and has been performed clinically in indicated disease. However, it have the problems for long-term storage of cord blood in liquid nitrogen and for limited application to adult due to small amount of hematopoietic stem cell. Therefore, several centers have carried out active research for ex vivo expansion of cord blood stem cell. We investigated the hematopoietic function of cord blood plasma for development of new techniques. METHODS: We acquired the nucleated cells of cord blood from healthy infant and bone marrow from healthy donor received granulocyte-colony stimulating factor. We evaluated hematopoietic colony formation according to source of stem cell and plasma by semisolid culture medium. Three experimental groups were divided as source of plasma: group for cord plasma, group for bone marrow plasma, group for mixture of cord plasma and bone marrow plasma. RESULTS: The results were as follows: 1) The colony formation according to source of stem cell in commercialized standard semisolid culture medium showed that cord blood in the number of CFU-GM was less than bone marrow, but not significantly different in CFU-GEMM. 2) The colony formation according to source of stem cell in semisolid culture medium using experimental plasma showed that cord blood in the number of CFU-GM was more than bone marrow. There were no cytotoxic effect of plasma to experimental cells. 3) The colony formation in semisolid culture medium contained plasma according to experimental group showed that the number of CFU-GM in cord blood plasma was significantly more than bone marrow plasma in spite of different source of stem cell. Conclusions: These results suggested that cord blood might contain enough hematopoiesis to enable to perform transplantation compared with bone marrow and, also, cord blood plasma might be contributed more effective colony formation than bone marrow plasma. Therefore, we propose that it may be good to store cord blood cells with cord blood plasma in long-term storage. We will investigate the composition of hematopoietic growth factors and cytokines in cord blood plasma and the effect of cord blood plasma for ex vivo expansion of cord blood cells.