Standardizing the freeze-thaw preparation of growth factors from platelet lysate.
Over the past decades, the focus on the regenerative properties of platelets (PLTs) has intensified and many PLT-derived growth factors are readily used in medical settings. A general lack of standardization in the preparation of these growth factors remains, however, and this study therefore examines the dynamics of growth factors throughout the freeze-thaw procedure.



Plateletpheresis (PA) and PLT-poor plasma (PPP) samples were collected from 10 healthy donors. PA was lysed to produce PLT lysate (PL) for 1, 3, 5, 10, and 30 freeze-thaw cycles. The resulting growth factor and cytokine concentrations from PPP, PA, and PL of different cycles were analyzed and compared using enzyme-linked immunosorbent assay and multiplex bead assays.



PL produced by the freeze-thaw procedure resulted in approximately four- to 10-fold enrichment of transforming growth factor-β1, epidermal growth factor, PLT-derived growth factor (PDGF)-AB/BB, PLT factor-4, and fibroblast growth factor-2. The increase in concentrations plateaued at Cycles 3 and 5 and in some cases declined with further cycles. The concentrations of insulin-like growth factor-1, hepatocyte growth factor, vascular endothelial growth factor, and bone morphogenetic protein-2 in PL were essentially comparable to those in PPP.



Using the freeze-thaw method, optimal preparation of PL with regard to the concentration of growth factors was achieved at Cycles 3 to 5. Based on our findings, the clinical significance of using a greater number of cycles is likely limited.
Department of Immunology, Genetics and Pathology, Section of Clinical Immunology, Uppsala University, Uppsala, Sweden.
Gabriel
G
Strandberg
Department of Immunology, Genetics and Pathology, Section of Clinical Immunology, Uppsala University, Uppsala, Sweden.
Felix
F
Sellberg
Department of Molecular Medicine and Surgery, Section of Plastic Surgery, Karolinska Institute and Karolinska University Hospital, Stockholm, Sweden.
Pehr
P
Sommar
Department of Immunology, Genetics and Pathology, Section of Clinical Immunology, Uppsala University, Uppsala, Sweden.
Martin
M
Ronaghi
Department of Immunology, Genetics and Pathology, Section of Clinical Immunology, Uppsala University, Uppsala, Sweden.
Norbert
N
Lubenow
Department of Immunology, Genetics and Pathology, Section of Clinical Immunology, Uppsala University, Uppsala, Sweden.
Folke
F
Knutson
Department of Immunology, Genetics and Pathology, Section of Clinical Immunology, Uppsala University, Uppsala, Sweden.
David
D
Berglund
D001792:Blood Platelets / Q000378:metabolism*; D001793:Blood Preservation; D015925:Cryopreservation; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D008297:Male; D008875:Middle Aged
D036341:Intercellular Signaling Peptides and Proteins