title: Composition of growth factors and cytokines in lysates obtained from fresh versus stored pathogen-inactivated platelet units.
abstract: BACKGROUND
  Platelet lysate is a readily available source of growth factors, and other mediators, which has been used in a variety of clinical applications. However, the product remains poorly standardized and the present investigation evaluates the composition of platelet lysate obtained from either fresh or stored pathogen-inactivated platelet units.
  
  
  METHODS
  Platelet pooled units (n = 10) were obtained from healthy blood donors and tested according to standard procedures. All units were pathogen inactivated using amotosalen hydrochloride and UVA exposure. Platelet lysate was subsequently produced at two separate time-points, either from fresh platelet units or after 5 days of storage, by repeated freeze-thaw cycles. The following mediators were determined at each time-point: EGF, FGF-2, VEGF, IGF-1, PDGF-AB/BB, BMP-2, PF4, TGF-β isoform 1, IL-1β, IL-2, IL-6, IL-10, IL-12p70, 1L-17A, TNF-α, and IFN-γ.
  
  
  RESULTS
  The concentration of growth factors and cytokines was affected by time in storage. Notably, TGF-β, PDGF-AB/BB, and PF4 showed an increase of 27.2% (p < 0.0001), 29.5% (p = 0.04) and 8.2% (p = 0.0004), respectively. A decrease was seen in the levels of IGF-1 and FGF-2 with 22% (p = 0.041) and 11% (p = 0.01), respectively. Cytokines were present only in very low concentrations and all other growth factors remained stable with time in storage.
  
  
  CONCLUSIONS
  The composition of mediators in platelet lysate obtained from pathogen-inactivated platelet units differs when produced from fresh and stored platelet units, respectively. This underscores the need for further standardization and optimization of this important product, which potentially may influence the clinical effects.
authors.affiliation: Department of Immunology, Genetics and Pathology, Section of Clinical Immunology, Uppsala University, Sweden.
authors.forename: Felix
authors.initials: F
authors.lastname: Sellberg
authors.affiliation: Department of Transplantation Surgery, Division of Transplantation Surgery, CLINTEC, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Berglund
authors.affiliation: Department of Immunology, Genetics and Pathology, Section of Clinical Immunology, Uppsala University, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Ronaghi
authors.affiliation: Department of Immunology, Genetics and Pathology, Section of Clinical Immunology, Uppsala University, Sweden.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Strandberg
authors.affiliation: Department of Immunology, Genetics and Pathology, Section of Clinical Immunology, Uppsala University, Sweden.
authors.forename: Helena
authors.initials: H
authors.lastname: Löf
authors.affiliation: Department of Molecular Medicine and Surgery, Section of Plastic Surgery, Karolinska Institute and Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Pehr
authors.initials: P
authors.lastname: Sommar
authors.affiliation: Department of Immunology, Genetics and Pathology, Section of Clinical Immunology, Uppsala University, Sweden.
authors.forename: Norbert
authors.initials: N
authors.lastname: Lubenow
authors.affiliation: Department of Immunology, Genetics and Pathology, Section of Clinical Immunology, Uppsala University, Sweden.
authors.forename: Folke
authors.initials: F
authors.lastname: Knutson
authors.affiliation: Department of Immunology, Genetics and Pathology, Section of Clinical Immunology, Uppsala University, Sweden. Electronic address: david.berglund@igp.uu.se.
authors.forename: David
authors.initials: D
authors.lastname: Berglund
mesh_terms: D001792:Blood Platelets / Q000378:metabolism*; D001793:Blood Preservation / Q000379:methods*; D002457:Cell Extracts / Q000737:chemistry*; D016207:Cytokines / Q000032:analysis*; D005260:Female; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000032:analysis*; D008297:Male; D050296:Microbial Viability; D008875:Middle Aged; D011785:Quality Assurance, Health Care; D013997:Time Factors
chemical_list: D002457:Cell Extracts; D016207:Cytokines; D036341:Intercellular Signaling Peptides and Proteins
keywords: Cytokine; Growth factor; Pathogen-inactivation; Platelet lysate