title: Tissue engineering rib with the incorporation of biodegradable polymer cage and BMSCs/decalcified bone: an experimental study in a canine model.
abstract: BACKGROUND
  The reconstruction of large bone defects, including rib defects, remains a challenge for surgeons. In this study, we used biodegradable polydioxanone (PDO) cages to tissue engineer ribs for the reconstruction of 4cm-long costal defects.
  
  
  METHODS
  PDO sutures were used to weave 6cm long and 1cm diameter cages. Demineralized bone matrix (DBM) which is a xenograft was molded into cuboids and seeded with second passage bone marrow mesenchymal stem cells (BMSCs) that had been osteogenically induced. Two DBM cuboids seeded with BMSCs were put into the PDO cage and used to reconstruct the costal defects. Radiographic examination including 3D reconstruction, histologic examination and mechanical test was performed after 24 postoperative weeks.
  
  
  RESULTS
  All the experimental subjects survived. In all groups, the PDO cage had completely degraded after 24 weeks and been replaced by fibrous tissue. Better shape and radian were achieved in PDO cages filled with DBM and BMSCs than in the other two groups (cages alone, or cages filled with acellular DBM cuboids). When the repaired ribs were subjected to an outer force, the ribs in the PDO cage/DBMs/BMSCs group kept their original shape while ribs in the other two groups deformed. In the PDO cage/DBMs/BMSCs groups, we also observed bony union at all the construct interfaces while there was no bony union observed in the other two groups. This result was also confirmed by radiographic and histologic examination.
  
  
  CONCLUSIONS
  This study demonstrates that biodegradable PDO cage in combination with two short BMSCs/DBM cuboids can repair large rib defects. The satisfactory repair rate suggests that this might be a feasible approach for large bone repair.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Shanghai Changzheng Hospital, The Second Military Medical University, No. 415 Fengyang Road, Shanghai 200003, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Tang
authors.forename: Bin
authors.initials: B
authors.lastname: Wu
authors.forename: Xiong
authors.initials: X
authors.lastname: Qin
authors.forename: Lu
authors.initials: L
authors.lastname: Zhang
authors.forename: Jim
authors.initials: J
authors.lastname: Kretlow
authors.forename: Zhifei
authors.initials: Z
authors.lastname: Xu
mesh_terms: D000818:Animals; D018786:Bone Substitutes / Q000737:chemistry; D004285:Dogs; D006651:Histocytochemistry; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000502:physiology; D016687:Polydioxanone / Q000737:chemistry*; D012272:Ribs / Q000293:injuries / Q000502:physiology*; D023822:Tissue Engineering / Q000295:instrumentation* / Q000379:methods*; D054457:Tissue Scaffolds; D014945:Wound Healing / Q000502:physiology
chemical_list: D018786:Bone Substitutes; D016687:Polydioxanone