Platelet-derived growth factors for GMP-compliant propagation of mesenchymal stromal cells

Stem cell-based therapies are a promising prospect for regenerative medicine. Particularly, human multipotent mesenchymal stromal cells (MSCs) are currently in focus regarding their regenerative and immune modulating capacities. An increasing number of clinical trials investigating MSC efficiency and safety are ongoing. Ex vivo propagation of human MSCs is considered to be a prerequisite for MSC therapy. The to date standard use of fetal bovine serum in cell culture bears risks including xenoimmunization and transmission of pathogens. Alternatively, human platelet-derived growth factors have been efficiently implemented into routine MSC expansion protocols. In compliance with good manufacturing practice we established an effective time- and resource-saving procedure for MSC propagation in an animal serum-free system. Bone marrow was seeded without manipulation directly in pooled human platelet lysate (pHPL) and L-glutamine supplemented minimum essential medium without antibiotics. Clinical scale expanded MSCs were harvested already after primary culture. MSC quality, identity, purity and function were assessed according to a defined panel of release criteria and comparative genomic hybridization was used to determine genomic stability. Because various potential risks of MSCs have recently been reported, further research is required to prove efficiency and long-term safety of human MSCs for cell therapy.