title: Platelet-rich concentrate supports human mesenchymal stem cell proliferation, bone morphogenetic protein-2 messenger RNA expression, alkaline phosphatase activity, and bone formation in vitro: a mode of action to enhance bone repair.
abstract: OBJECTIVE
  Platelet-rich concentrate (PRC) is an autologous growth factor preparation that is in routine use for orthopaedic and maxillofacial surgery. However, there are little data available describing the cellular and molecular mechanisms by which PRC enhances the healing response in an osseous environment. The aim of this study was to identify cellular and molecular events that are modulated in human mesenchymal stem cells (hMSCs) in response to exposure to human PRC generated by a novel filtration-based device (CAPTION, Smith & Nephew Inc).
  
  
  METHODS
  PRC and serum were prepared from blood donated by 11 volunteers. Growth factor content and release from PRC were determined by enzyme-linked immunosorbent assay. Cell proliferation was quantified by DNA content and osteoblastic differentiation by alkaline phosphatase expression and mineralized nodule formation. Real-time reverse transcription-polymerase chain reaction analysis was used to determine the early molecular pathways regulated in hMSCs by PRC.
  
  
  RESULTS
  The results obtained confirm previous in vitro and in vivo observations demonstrating that PRC enhances hMSC proliferation. Furthermore, our data suggest that when added as a clot, PRC induces an earlier onset of proliferation compared with serum without leading to cell overgrowth and the inhibition of cell differentiation. At the molecular level, PRC treatment stimulated a transient enhancement of bone morphogenetic protein-2 messenger RNA that peaked after 12 hours and induced an earlier and a sustained increase in the key osteogenic transcription factor RUNX2. By 3 days of treatment, PRC enhanced alkaline phosphatase activity more than 2-fold compared with donor-matched serum, and at 23 days, the increase in osteoblastic commitment translated to enhanced calcified matrix deposition.
  
  
  CONCLUSIONS
  Taken together, the data presented here suggest that treatment of hMSC with clotted PRC, in an osteoinductive environment, enhances osteoblastic commitment and bone formation. Furthermore, these data indicate that the enhanced osteogenesis seen in the presence of PRC cannot be explained solely by enhanced cell proliferation, suggesting that PRC modulates a number of cell and molecular pathways to promote bone formation.
authors.affiliation: Smith & Nephew Research Centre, Heslington, York, UK.
authors.forename: Philippa
authors.initials: P
authors.lastname: Parsons
authors.forename: Andrew
authors.initials: A
authors.lastname: Butcher
authors.forename: Katy
authors.initials: K
authors.lastname: Hesselden
authors.forename: Keith
authors.initials: K
authors.lastname: Ellis
authors.forename: Jonathan
authors.initials: J
authors.lastname: Maughan
authors.forename: Richard
authors.initials: R
authors.lastname: Milner
authors.forename: Marcus
authors.initials: M
authors.lastname: Scott
authors.forename: Carie
authors.initials: C
authors.lastname: Alley
authors.forename: J Tracy
authors.initials: JT
authors.lastname: Watson
authors.forename: Alan
authors.initials: A
authors.lastname: Horner
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism*; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics / Q000378:metabolism*; D001861:Bone Regeneration / Q000502:physiology*; D018929:Cell Culture Techniques / Q000379:methods; D049109:Cell Proliferation; D002478:Cells, Cultured; D004789:Enzyme Activation; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000502:physiology*; D010012:Osteogenesis / Q000502:physiology*; D053657:Platelet-Rich Plasma / Q000378:metabolism*; D012313:RNA / Q000378:metabolism
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D012313:RNA; D000469:Alkaline Phosphatase