Generation of a pool of human platelet lysate and efficient use in cell culture.

Human platelets represent a promising source of bioactive substances as growth factors not just for in vivo wound healing and tissue repair, but also for the expansion of human stem and progenitor cells in vitro. The replacement of fetal bovine serum (FBS) as a standard culture supplement by human platelet-derived growth factors now allows for the GMP-compliant implementation of various cell therapeutics in the growing field of regenerative medicine.For this purpose a protocol for the preparation of human platelet lysate (HPL) by several freeze-thaw cycles has been developed, resulting in platelet fragmentation and the release of stored growth factors. By pooling up to 15 U of HPL derived from individual blood donors, a virtually standardized product is achieved. The depletion of platelet particles and fragments in a final centrifugation step reduces the risk of alloimmunization against platelet antigens and the formation of aggregates in cell culture.The successful application of pooled human platelet lysate (pHPL) as a culture medium supplement for the ex vivo propagation of human mesenchymal stem/progenitor cells (MSPCs) and endothelial colony forming progenitor cells (ECFCs) indicates the feasibility of this animal serum-free source of growth factors. Further studies will evaluate efficacy and safety of pHPL.