Metabolically conditioned media derived from bone marrow stromal cells or human skin fibroblasts act as effective chemoattractants for mesenchymal stem cells

BACKGROUND: The main goal of bone tissue engineering has been the generation of healthy bone in order to replace affected tissue. Therefore, optimized biomaterials are needed which allow the survival and growth of mesenchymal stem cells. Until now the key challenge in the clinical application of cell-based tissue engineering bone implants was poor diffusion of oxygen into the tissue, making functional blood vessel networks a necessity. With their ability to evolve into different cell types, to expand extensively in vitro, and to release paracrine soluble factors, bone marrow stromal cells (BMSC) are highly attractive for tissue engineering. During the last years hypoxia became a proven method to control proliferation, differentiation, and pluripotency of BMSC. Here we applied different methods to characterize metabolically conditioned media (MCM) in comparison to hypoxia conditioned media (HCM) and evaluated their ability to attract BMSC in 2-D migration assays. METHODS: BMSC and fibroblasts of human origin were isolated and cultivated to obtain HCM and MCM. Both media were characterized by angiogenesis arrays, cytokine arrays, and ELISA for selected factors. 2-D migration tests were performed with Corning Transwell®-96 permeable support chambers with porous polyester membranes with a pore size of 8.0 μm. RESULTS: Characterization of HCM and MCM revealed that the concentration of angiogenic factors was higher in MCM than in HCM. However, the chemoattractive capacity of MCM for BMSC was equivalent to that of HCM. HCM and MCM produced by human skin fibroblasts attracted human BMSC as efficiently as HCM and MCM produced by human BMSC. CONCLUSIONS: HCM and MCM have a high chemoattractive capacity for BMSC. Both conditioned media harbor high concentrations of angiogenic factors which are important for angiogenesis and cell migration. Both chemoattracting conditioned media can also be derived from skin fibroblasts which can easily be obtained from patients in individualized therapy approaches.