title: Bioengineered periosteal progenitor cell sheets to enhance tendon-bone healing in a bone tunnel.
abstract: BACKGROUND
  Tendon-bone tunnel healing is crucial for long term success in anterior cruciate ligament (ACL) reconstruction. The periosteum contains osteochondral progenitor cells that can differentiate into osteoblasts and chondroblasts during tendon-bone healing. We developed a scaffold-free method using polymerized fibrin-coated dishes to make functional periosteal progenitor cell (PPC) sheets. Bioengineered PPC sheets for enhancing tendon-bone healing were evaluated in an extra-articular bone tunnel model in rabbit.
  
  
  METHODS
  PPC derived from rabbit tibia periosteum, cultivated on polymerized fibrin-coated dishes and harvested as PPC sheet. A confocal microscopy assay was used to evaluate the morphology of PPC sheets. PPC sheets as a periosteum to wrap around hamstring tendon grafts were pulled into a 3-mm diameter bone tunnel of tibia, and compared with a tendon graft without PPC sheets treatment. Rabbits were sacrificed at 4 and 8 weeks postoperatively for biochemical as-say and histological assay to demonstrate the enhancement of PPC sheets in tendon-bone healing.
  
  
  RESULTS
  PPC spread deposit on fibrin on the dish surface with continuous monolayer PPC was ob-served. Histological staining revealed that PPC sheets enhance collagen and glycosaminoglycans deposition with fibrocartilage formation in the tendon-bone junction at 4 weeks. Collagen fiber with fibrocartilage formation at tendon-bone junction was also found at 8 weeks. Matured fibrocartilage and dense collagen fiber were formed at the tendon-bone interface at 8 weeks by Masson trichrome and Safranin-O staining.
  
  
  CONCLUSIONS
  Periosteal progenitor cell monolayer maintains the differentiated capacity and osteochondral potential in order to promote fibrocartilage formation in tendon-bone junction. Bioengineered PPC sheets can offer a new feasible therapeutic strategy of a novel approach to enhance tendon-bone junction healing.
authors: Department of Orthopaedic Surgery, Chang Gung Memorial Hospital at Keelung, Chang Gung University College of Medicine, Taoyuan, Taiwan.
authors: Chih-Hsiang
authors: CH
authors: Chang
authors: Chih-Hwa
authors: CH
authors: Chen
authors: Hsia-Wei
authors: HW
authors: Liu
authors: Shu-Wen
authors: SW
authors: Whu
authors: Shih-Hui
authors: SH
authors: Chen
authors: Ching-Lin
authors: CL
authors: Tsai
authors: Ging-Ho
authors: GH
authors: Hsiue
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery / Q000637:transplantation*; D001842:Bone and Bones / Q000601:surgery*; D010012:Osteogenesis / Q000502:physiology; D010521:Periosteum / Q000473:pathology / Q000601:surgery*; D011817:Rabbits; D013234:Stem Cells / Q000166:cytology*; D013710:Tendons / Q000473:pathology / Q000601:surgery*; D013977:Tibia / Q000601:surgery / Q000637:transplantation*; D014182:Transplantation, Autologous / Q000379:methods; D014945:Wound Healing / Q000502:physiology