Phenotypic and functional characterization of human bone marrow stromal cells in hollow-fibre bioreactors.

The transplantation of human bone marrow stromal cells (BMSCs) is a novel immunotherapeutic approach that is currently being explored in many clinical settings. Evidence suggests that the efficacy of cell transplantation is directly associated with soluble factors released by human BMSCs. In order to harness these secreted factors, we integrated BMSCs into large-scale hollow-fibre bioreactor devices in which the cells, separated by a semipermeable polyethersulphone (PES) membrane, can directly and continuously release therapeutic factors into the blood stream. BMSCs were found to be rapidly adherent and exhibited long-term viability on PES fibres. The cells also preserved their immunophenotype under physiological fluid flow rates in the bioreactor, and exhibited no signs of differentiation during device operation, but still retained the capacity to differentiate into osteoblastic lineages. BMSC devices released growth factors and cytokines at comparable levels on a per-cell basis to conventional cell culture platforms. Finally, we utilized a potency assay to demonstrate the therapeutic potential of the collected secreted factors from the BMSC devices. In summary, we have shown that culturing BMSCs in a large-scale hollow-fibre bioreactor is feasible without deleterious effects on phenotype, thus providing a platform for collecting and delivering the paracrine secretions of these cells.