title: Growth factor and catabolic cytokine concentrations are influenced by the cellular composition of platelet-rich plasma.
abstract: BACKGROUND
  Previous studies of bioactive molecules in platelet-rich plasma (PRP) have documented growth factor concentrations that promote tissue healing. However, the effects of leukocytes and inflammatory molecules in PRP have not been defined.
  
  
  OBJECTIVE
  The hypothesis for this study was that the concentration of growth factors and catabolic cytokines would be dependent on the cellular composition of PRP.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Platelet-rich plasma was made from 11 human volunteers using 2 commercial systems: Arthrex ACP (Autologous Conditioned Plasma) Double Syringe System (PRP-1), which concentrates platelets and minimizes leukocytes, and Biomet GPS III Mini Platelet Concentrate System (PRP-2), which concentrates both platelets and leukocytes. Transforming growth factor-β1 (TGF-β1), platelet-derived growth factor-AB (PDGF-AB), matrix metalloproteinase-9 (MMP-9), and interleukin-1β (IL-1β) were measured with enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  The PRP-1 system consisted of concentrated platelets (1.99×) and diminished leukocytes (0.13×) compared with blood, while PRP-2 contained concentrated platelets (4.69×) and leukocytes (4.26×) compared with blood. Growth factors were significantly increased in PRP-2 compared with PRP-1 (TGF-β1: PRP-2 = 89 ng/mL, PRP-1 = 20 ng/mL, P < .05; PDGF-AB: PRP-2 = 22 ng/mL, PRP-1 = 6.4 ng/mL, P < .05). The PRP-1 system did not have a higher concentration of PDGF-AB compared with whole blood. Catabolic cytokines were significantly increased in PRP-2 compared with PRP-1 (MMP-9: PRP-2 = 222 ng/mL, PRP-1 = 40 ng/mL, P < .05; IL-1β: PRP-2 = 3.67 pg/mL, PRP-1 = 0.31 pg/mL, P < .05). Significant, positive correlations were found between TGF-β1 and platelets (r(2) = .75, P < .001), PDGF-AB and platelets (r(2) = .60, P < .001), MMP-9 and neutrophils (r(2) = .37, P < .001), IL-1β and neutrophils (r(2) = .73, P < .001), and IL-1β and monocytes (r(2) = .75, P < .001).
  
  
  CONCLUSIONS
  Growth factor and catabolic cytokine concentrations were influenced by the cellular composition of PRP. Platelets increased anabolic signaling and, in contrast, leukocytes increased catabolic signaling molecules. Platelet-rich plasma products should be analyzed for content of platelets and leukocytes as both can influence the biologic effects of PRP.
  
  
  CONCLUSIONS
  Depending on the clinical application, preparations of PRP should be considered based on their ability to concentrate platelets and leukocytes with sensitivity to pathologic conditions that will benefit most from increased platelet or reduced leukocyte concentration.
authors.affiliation: Department of Clinical Sciences, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Emily A
authors.initials: EA
authors.lastname: Sundman
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Cole
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Fortier
mesh_terms: D016207:Cytokines / Q000032:analysis / Q000097:blood*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000032:analysis / Q000097:blood*; D009504:Neutrophils; D053657:Platelet-Rich Plasma / Q000737:chemistry*
chemical_list: D016207:Cytokines; D036341:Intercellular Signaling Peptides and Proteins