title: Platelet-rich plasma for bone healing and regeneration.
abstract: BACKGROUND
  Successful healing of large bone defects (LBDs) is a complicated phenomenon because the body's natural ability often fails to effectively repair the LBDs. New modalities should be utilized to increase the quality and accelerate bone healing. Platelet concentrates in different forms can be considered an attractive option for such purpose.
  
  
  METHODS
  Platelets as a natural source of growth factors, cytokines, and other micro and macromolecules are hypothesized to improve bone healing. This review has covered important concepts regarding platelet-rich plasma (PRP) including mechanisms of action, preparation protocols and their differences, and factors affecting the PRP efficacy during bone healing. In addition, the most recent studies in different levels which evaluated the role of PRP on bone repair has been reviewed and discussed to clarify the controversies and conflicts, and to illustrate a future prospective and directions for orthopedic surgeons to overcome current limitations and difficulties.
  
  
  CONCLUSIONS
  As the efficacy of PRP is dependent on various factors, the outcome of PRP therapy is variable and unpredictable in orthopedic patients. Therefore, it is still too soon to suggest PRP as the first line treatment option in complicated bone injuries such as LBDs and nonunions. However, combination of PRP with natural and synthetic biomaterials can enhance the effectiveness of PRP.
authors.affiliation: a Department of Pathology , School of Veterinary Medicine, Shiraz University , Shiraz , Iran.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Oryan
authors.affiliation: a Department of Pathology , School of Veterinary Medicine, Shiraz University , Shiraz , Iran.
authors.forename: Soodeh
authors.initials: S
authors.lastname: Alidadi
authors.affiliation: b Department of Pharmacology, RAZI Drug Research Center, School of Medicine , Iran University of Medical Sciences , Tehran , Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Moshiri
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000502:physiology; D001847:Bone Diseases / Q000378:metabolism / Q000628:therapy*; D001861:Bone Regeneration / Q000502:physiology*; D006801:Humans; D018836:Inflammation Mediators / Q000037:antagonists & inhibitors / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology / Q000627:therapeutic use; D053657:Platelet-Rich Plasma / Q000502:physiology*; D011446:Prospective Studies; D014945:Wound Healing / Q000502:physiology*
chemical_list: D018836:Inflammation Mediators; D036341:Intercellular Signaling Peptides and Proteins
keywords: Bone healing; growth factors; inflammatory cytokines; platelet-rich plasma