Platelet lysate for cell therapy and regenerative medicine

摘要

Cell cultures for cell therapy and regenerative medicine products are mainly performed in the presence of fetal calf serum (FCS). Due to its animal origin, the use of FCS bears the risk of prion disease transmission or immunogenicity of xenogeneic proteins. Several studies are already published that replaced FCS by human serum or use of defined media where recombinant growth factors were added. Due to its high concentrations in growth factors (GF), human platelet lysate (hPL) also turned out to be a potential substitute for FCS. Our aim was to develop a production process according to GMP requirements for hPL to be used in cell culture. At the beginning, hPL was made out of outdated thrombocyte pools. The concentrates were stored at 80??C and thawed in a water bath at +37??C to cause platelet lysis. hPL was compared to FCS in several proliferation studies including adipose tissue derived stem cells (ASC), amniotic mesenchymal stroma cells, fibroblasts and chondrocytes. Furthermore, differentiation of ASC in presence of hPL as well as redifferentiation of chondrocytes cultured with hPL was achieved. In all these studies lower amounts of hPL were needed to obtain equal or superior results compared to FCS. However, there is only a low amount of thrombocyte pools which need to be discarded and heparin needs to be added to the medium to avoid gel formation. Therefore, process adaptation was performed. Buffy coats with too low plasma levels that would be discarded are used. The plasma is replaced by 0.9% sodium chloride solution and volume reduction as well as increase in platelet concentration was achieved by centrifugation. Finally, several freeze thaw cycles were performed to achieve the highest yield in GF