Lyophilized human platelet lysate from platelet concentrates for cell biology research and manufacturing of cell therapy products

A significant number of platelet concentrates (PCs) is discarded daily due to limited shelf life. Human platelet lysate (HPL), derived from expired PCs, can serve as an ethical and sustainable alternative to fetal calf serum in biomedical research. We developed a method to produce HPL under GMP conditions for basic research and cell-based therapeutics. We follow the overall aim to enhance the applicability of HPL by lyophilization (L-HPL) leading to increased storage temperature and shelf life.

Four pooled PCs, consisting of cell material from four donors each, were lysed by successive freezing and thawing cycles. The cell debris was separated by centrifugation and the supernatant was lyophilized. We compared HPL and L-HPL regarding their quality parameters pH, total protein, osmolality, sodium, potassium and chloride concentration and analyzed the concentrations of 13 growth factors (e.g. TGF-ß1, VEGF, bFGF). Additionally, we determined the cell yield and proliferation capacity of human mesenchymal stem cells (hMSCs) following expansion in cell culture media containing FCS, HPL and reconstituted L-HPL as well as the potential of hMSCs for adipogenic, chondrogenic and osteogenic differentiation following expansion.

The quality parameters pH, total protein, osmolality, sodium, potassium and chloride concentration and growth factor concentrations are comparable between HPL and reconstituted L-HPL. Cell yield and proliferation capacity of hMSCs was significantly enhanced following culture in media containing HPL or reconstituted L-HPL if compared to cells cultured in FCS containing medium. Significant differences between hMSCs cultured in media containing HPL or reconstituted L-HPL in terms of proliferation capacity and differentiation potential were not detected (figure 1).

We successfully developed a GMP-compliant method to produce well-applicable lyophilized HPL from expired PCs. The comparison of L-HPL with HPL revealed comparable quality parameters and growth factor concentrations, demonstrating the viability of L-HPL as a cell culture substitute. Notably, culture in media containing HPL or L-HPL proved increased cell yield, offering a more efficient and economical approach in comparison to FCS.

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