Comparison of ex vivo expansion culture conditions of mesenchymal stem cells for human cell therapy

Background: Mesenchymal stem cells (MSCs) are multipotent stem cells. Based on their properties, several clinical trials have been designed to explore their potential therapeutic effect. Fetal calf serum (FCS, commonly used for in vitro expansion) is an undesirable source of xenogeneic antigens and bears the risk of transmitting contaminations. As an alternative for FCS, platelet lysate (PL) and both autologous and allogeneic human serum have been proposed. The aim of this study is to compare the culture of bone marrow (BM)-derived MSCs in the presence of different serum supplements to determine the effect on cell growth, differentiation potential, and immunologic function.

Study design and methods: MSCs from BM of healthy volunteer donors were grown in the presence of 10% FCS supplemented with 1 ng/mL basic fibroblast growth factor (bFGF), 10% human serum supplemented with 1 ng/mL bFGF, 5% PL, and PL 5% supplemented with 1 ng/mL bFGF (PL plus bFGF).

Results: MSCs that expanded in either medium showed a comparable morphology, phenotype, and proliferative and differentiation capacity. While the presence of MSCs in vitro significantly decreased CD3/CD28-mediated T-cell activation, this effect was significantly higher in MSCs cultured with human serum. Production of interferon-gamma was inhibited by cocultured media with MSCs while MSCs also induced a significant inhibition of cell cycle in T cells.

Discussion: In conclusion, PL or autologous serum could offer an alternative to the use of FCS in MSC expansion for clinical use maintaining the same growing potential, phenotype, immunomodulatory properties, and differentiation potential.