title: Differential growth factor retention by platelet-rich plasma composites.
abstract: OBJECTIVE
  This study evaluates the temporal sequence and growth factor release from platelet-rich plasma (PRP) combined with different bone substitutes (BS), to identify an optimal substrate for extended growth factor retention.
  
  
  METHODS
  PRP was clotted with bovine thrombin or thrombin receptor activator peptide-6 (TRAP). In addition, PRP was clotted using Allogro (Ceramed, Lakewood, CO), BioGlass (Mo-Sci, Rolla, MN), or BioOss (Osteohealth, Shirley, NY). The effects of media exchange and BS on platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF beta) release were quantified via enzyme-linked immunosorbent assay.
  
  
  RESULTS
  At day 1, the thrombin group released 36% more PDGF than the TRAP group and 80% more than the BS groups. At 7 days, PDGF release was the greatest for the TRAP group. PDGF release was minimal for all groups at day 14, with BS groups retaining 60% more PDGF than thrombin clots. Similarly, the thrombin group released the greatest amount of TGF beta (81.4% of the total), whereas TRAP and BS groups released significantly less TGF beta at day 1. Compared with thrombin, TRAP retained 39.2% more TGF beta, whereas BS groups retained even greater levels (Allogro, 54.3%; BioOss, 45.8%; BioGlass, 67.0%). No significant difference in TGF beta release was observed among the substitutes after day 1. The BS groups continued to retain TGF beta after 14 days, whereas all TGF beta in the thrombin clots was depleted.
  
  
  CONCLUSIONS
  PRP preparation with thrombin results in a large, immediate release of growth factors that could be lost into the interstitium in vivo. TRAP-BS may prove more efficacious than thrombin in sustaining growth factor levels critical for the cascade of events leading to bone formation.
authors.affiliation: Division of Oral and Maxillofacial Surgery, School of Dental and Oral Surgery, Columbia University, New York, NY 1032, USA.
authors.forename: Rick C
authors.initials: RC
authors.lastname: Tsay
authors.forename: Jennifer
authors.initials: J
authors.lastname: Vo
authors.forename: Andrea
authors.initials: A
authors.lastname: Burke
authors.forename: Sidney B
authors.initials: SB
authors.lastname: Eisig
authors.forename: Helen H
authors.initials: HH
authors.lastname: Lu
authors.forename: Regina
authors.initials: R
authors.lastname: Landesberg
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D001861:Bone Regeneration / Q000187:drug effects / Q000502:physiology; D018786:Bone Substitutes / Q000378:metabolism*; D002417:Cattle; D002516:Ceramics / Q000378:metabolism; D006133:Growth Substances / Q000097:blood*; D006801:Humans; D010446:Peptide Fragments / Q000097:blood; D010982:Platelet-Derived Growth Factor / Q000096:biosynthesis; D013917:Thrombin / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000097:blood
chemical_list: C022107:Bioglass; D018786:Bone Substitutes; D006133:Growth Substances; D010446:Peptide Fragments; D010982:Platelet-Derived Growth Factor; D016212:Transforming Growth Factor beta; C082835:thrombin receptor peptide (42-47); D013917:Thrombin