title: Platelet autologous growth factors decrease the osteochondral regeneration capability of a collagen-hydroxyapatite scaffold in a sheep model.
abstract: BACKGROUND
  Current research aims to develop innovative approaches to improve chondral and osteochondral regeneration. The objective of this study was to investigate the regenerative potential of platelet-rich plasma (PRP) to enhance the repair process of a collagen-hydroxyapatite scaffold in osteochondral defects in a sheep model.
  
  
  METHODS
  PRP was added to a new, multi-layer gradient, nanocomposite scaffold that was obtained by nucleating collagen fibrils with hydroxyapatite nanoparticles. Twenty-four osteochondral lesions were created in sheep femoral condyles. The animals were randomised to three treatment groups: scaffold, scaffold loaded with autologous PRP, and empty defect (control). The animals were sacrificed and evaluated six months after surgery.
  
  
  RESULTS
  Gross evaluation and histology of the specimens showed good integration of the chondral surface in both treatment groups. Significantly better bone regeneration and cartilage surface reconstruction were observed in the group treated with the scaffold alone. Incomplete bone regeneration and irregular cartilage surface integration were observed in the group treated with the scaffold where PRP was added. In the control group, no bone and cartilage defect healing occurred; defects were filled with fibrous tissue. Quantitative macroscopic and histological score evaluations confirmed the qualitative trends observed.
  
  
  CONCLUSIONS
  The hydroxyapatite-collagen scaffold enhanced osteochondral lesion repair, but the combination with platelet growth factors did not have an additive effect; on the contrary, PRP administration had a negative effect on the results obtained by disturbing the regenerative process. In the scaffold + PRP group, highly amorphous cartilaginous repair tissue and poorly spatially organised underlying bone tissue were found.
authors.affiliation: Biomechanics Laboratory-Rizzoli Orthopaedic Institute, Bologna, Italy. e.kon@biomec.ior.it
authors.forename: Elizaveta
authors.initials: E
authors.lastname: Kon
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Filardo
authors.forename: Marco
authors.initials: M
authors.lastname: Delcogliano
authors.forename: Milena
authors.initials: M
authors.lastname: Fini
authors.forename: Francesca
authors.initials: F
authors.lastname: Salamanna
authors.forename: Gianluca
authors.initials: G
authors.lastname: Giavaresi
authors.forename: Ivan
authors.initials: I
authors.lastname: Martin
authors.forename: Maurilio
authors.initials: M
authors.lastname: Marcacci
mesh_terms: D000818:Animals; D001861:Bone Regeneration / Q000502:physiology*; D004195:Disease Models, Animal; D005260:Female; D017713:Platelet Transfusion / Q000379:methods*; D010982:Platelet-Derived Growth Factor / Q000008:administration & dosage* / Q000378:metabolism / Q000627:therapeutic use*; D053657:Platelet-Rich Plasma; D019919:Prosthesis Implantation / Q000379:methods*; D011897:Random Allocation; D034561:Sheep, Domestic; D054457:Tissue Scaffolds / Q000592:standards*
chemical_list: D010982:Platelet-Derived Growth Factor