Bone marrow stromal cells prepared using AB serum and bFGF for hematopoietic stem cells expansion

BACKGROUND: An ex vivo culture system was previously established for stem cell expansion using human marrow stromal cells and serum-free medium. However, the stromal cells were prepared using long-term culture medium containing horse serum and FCS, which may transmit infectious diseases of xenogeneic origin. In this study, therefore, a method was established to prepare stromal cells using an AB serum-based medium. In the case that serum from a transplant recipient or PBPC donor is available, additional infectious diseases would not be transmitted. STUDY DESIGN AND METHODS: Cord blood CD34+ cells were cultured with thrombopoietin, stem cell factor, and flt3/flk2 ligand on a monolayer of human marrow primary stromal cells prepared using long-term culture medium or AB serum-based medium. After 2 weeks, clonogenic progenitor activity and SCID mouse-reconstituting cell activity were assayed. mRNA expression of cytokines and Notch ligand by stromal cells was also examined. RESULTS: There were no remarkable differences in expansion-supporting activity and mRNA expression between stromal cells established by the two methods. CONCLUSION: An ex vivo expansion system completely based on AB serum has been established.