title: Cell sheet transplantation of cultured mesenchymal stem cells enhances bone formation in a rat nonunion model.
abstract: Orthopedic surgeons have long been troubled by cases involving nonunion of fractured bones. This study aimed to enhance bone union by cell sheet transplantation of mesenchymal stem cells. A nonunion model was made in rat femur, and rat bone marrow cells were cultured in medium containing dexamethasone and ascorbic acid phosphate to create a cell sheet that could be scraped off as a single sheet. Cell sheets were transplanted onto fractured femurs without a scaffold in the model. X-ray and histological analysis were performed at 2, 4 and 8 weeks. Ultrasonography and biomechanical analysis were performed at 8 weeks. X-ray photographs and histological sections showed callus formation around the fracture site in the cell sheet-transplanted group (sheet group). Bone union was obtained in the sheet group at 8 weeks. By contrast, the control group (without sheet transplantation) showed nonunion of the femur. The results of pullout evaluation in the vertical direction of the femur in the sheet group were significantly better than that of the control group. Analysis of the origin of de novo formed bone using the Sry gene, which was used as a marker for donor cells, showed that transplanted cells without scaffolds could survive and differentiate into osteogenic lineage cells in vivo. These results showed that the femoral fracture in our model was completely cured by the transplantation of a cell sheet created by tissue engineering techniques. Thus, we think that cell sheet transplantation can contribute to hard tissue reconstruction in cases involving nonunion, bone defects and osteonecrosis.
authors.affiliation: Department of Orthopedic Surgery, Nara Medical University School of Medicine, Kashihara, Nara 634-8522, Japan.
authors.forename: Akifumi
authors.initials: A
authors.lastname: Nakamura
authors.forename: Manabu
authors.initials: M
authors.lastname: Akahane
authors.forename: Hideki
authors.initials: H
authors.lastname: Shigematsu
authors.forename: Mika
authors.initials: M
authors.lastname: Tadokoro
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Morita
authors.forename: Hajime
authors.initials: H
authors.lastname: Ohgushi
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Dohi
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Imamura
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Tanaka
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001696:Biomechanical Phenomena; D002478:Cells, Cultured; D004195:Disease Models, Animal; D005599:Fractures, Ununited / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*; D005786:Gene Expression Regulation; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D015675:Osteocalcin / Q000235:genetics / Q000378:metabolism; D010012:Osteogenesis / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011859:Radiography; D051381:Rats; D011916:Rats, Inbred F344; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014463:Ultrasonography; D014998:Y Chromosome / Q000235:genetics
chemical_list: D012333:RNA, Messenger; D015675:Osteocalcin; D000469:Alkaline Phosphatase