title: Platelet-rich plasma activation in combination with biphasic osteochondral scaffolds-conditions for maximal growth factor production.
abstract: OBJECTIVE
  The combination of scaffolds and biological factors may enhance articular cartilage repair. Little is known regarding the activation and subsequent growth factor release of platelet-rich plasma (PRP) in contact with biosynthetic scaffolds. The purpose of this study was i) to identify whether the addition of thrombin was required to activate PRP in the presence of a collagen osteochondral scaffold and ii) to compare the activity of PRP when applied to both collagen- and polylactide-based osteochondral scaffolds.
  
  
  METHODS
  Equal combined volumes of test substances were used (n = 3): 500 μl PRP alone or on scaffolds; 375 μl PRP + 125 μl autologous thrombin on scaffolds; 455 μl PRP + 45 μl bovine thrombin on scaffolds. Scaffolds and/or PRP were cultured in vitro in DMEM/F12 medium for 10 days. TGF-β1, PDGF-AB and bFGF were measured using ELISA.
  
  
  RESULTS
  A similar cumulative release profile in all growth factors was found over the 10-day period i.e. a burst release and further physiological prolonged release. A significantly higher release of PDGF-AB was seen in the PRP + collagen scaffold groups at all time points, compared to scaffold + PRP + thrombins (P < 0.001). A significantly increased cumulative volume of PDGF-AB was released from the collagen scaffold compared to the polylactide scaffold (P < 0.001).
  
  
  CONCLUSIONS
  This study shows that polylactide and particularly collagen osteochondral scaffolds activate PRP in vitro. If PRP is combined with these scaffolds clinically, no exogenous activation with thrombin is required to achieve growth factor release, which may be of benefit for articular cartilage repair applications.
authors.affiliation: Addenbrooke's Hospital, The University of Cambridge Orthopaedic Research Unit, Box 180, Hills Road, Cambridge CB2 2QQ, UK. agetgood@btinternet.com
authors.forename: Alan
authors.initials: A
authors.lastname: Getgood
authors.forename: Frances
authors.initials: F
authors.lastname: Henson
authors.forename: Roger
authors.initials: R
authors.lastname: Brooks
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Fortier
authors.forename: Neil
authors.initials: N
authors.lastname: Rushton
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology / Q000378:metabolism*; D002417:Cattle; D004797:Enzyme-Linked Immunosorbent Assay; D005346:Fibroblast Growth Factors / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D010982:Platelet-Derived Growth Factor / Q000378:metabolism; D053657:Platelet-Rich Plasma; D013917:Thrombin / Q000494:pharmacology; D054457:Tissue Scaffolds; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D010982:Platelet-Derived Growth Factor; D016212:Transforming Growth Factor beta; C095477:platelet-derived growth factor AB; D005346:Fibroblast Growth Factors; D013917:Thrombin