Growth factor release from platelet concentrates: analytic quantification and characterization for clinical applications.

BACKGROUND AND OBJECTIVES: Clinical use of plasma rich in growth factors requires biochemical product control. We aimed to measure and modulate concentrations of growth factors in solutions deriving from platelet apheresis or whole blood. MATERIALS AND METHODS: Growth factor concentrations were measured 5', 10', 20', 30', 60' after CaCl2 was added at 40°C to platelet-apheresis products (n = 39) or after 60' in platelet concentrates from whole blood (n = 13). Growth factor release was also obtained in platelet apheresis a) by incubation at 22°C or 40°C for 10' or 30' (n = 4); b) by repeated freeze-thaw (n = 9). RESULTS: Fibroblast growth factor (FGF), platelet-derived growth factor (PDGF) isoforms AA and AB and transforming growth factor beta (TGF-ß) concentrations (pg/10(9 ) plt) were 25-60% higher in growth factors solutions from whole blood compared to platelet apheresis. Vascular endothelial growth factor (VEGF), TGF-ß and PDGF isoforms were released early (5-10') during incubation: TGF-ß concentration increased also at 30'. FGF and epidermal growth factor (EGF) were released only after 30'. Incubation at 40°C/10' increased VEGF (+70%) and decreased EGF (-30%) and PDGF-BB (-50%) versus 22°C/30'. Shock significantly increased TGF-ß (1.6-fold), EGF (1.5-fold), FGF (4.5-fold) and lowered PDGF isoforms (0.2- to 0.5-fold) versus prolonged incubation at 40°C. CONCLUSION: Platelets from platelet apheresis and whole-blood release all investigated growth factors. The release can be regulated controlling incubation time and/or temperature and performing cell lysis.

Long term cryopreservation in 5% DMSO maintains unchanged CD34(+) cells viability and allows satisfactory hematological engraftment after peripheral blood stem cell transplantation.

Peripheral blood stem cell cryopreservation is associated with cell damage and decreased viability. We evaluated the impact of up to 10 years of cryopreservation (5% DMSO) on viability of CD34(+) cells utilizing graft samples of consecutive patients (2002-2012) with different malignancies who underwent stem cell collection and transplantation. Viability of CD34(+) cells from oncohaematological patients measured after 5 weeks (97·2 ± 0·6%) or after 9-10 years of cryopreservation (95·9 ± 0·5%) was unaffected. Haemoglobin, granulocyte and platelet recovery after transplantation of long-term cryopreserved grafts occurred within 8-13 days. CD34(+) stem cells can be safely stored up to 9-10 years, without affecting cell viability and clinical effectiveness.