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 degrees 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 degrees C or 40 degrees 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-beta) 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-beta and PDGF isoforms were released early (5-10') during incubation: TGF-beta concentration increased also at 30'. FGF and epidermal growth factor (EGF) were released only after 30'. Incubation at 40 degrees C/10' increased VEGF (+70%) and decreased EGF (-30%) and PDGF-BB (-50%) versus 22 degrees C/30'. Shock significantly increased TGF-beta (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 degrees 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.