title: Cartilage repair using bone morphogenetic protein 4 and muscle-derived stem cells.
abstract: OBJECTIVE
  Muscle-derived stem cells (MDSCs) isolated from mouse skeletal muscle exhibit long-time proliferation, high self-renewal, and multipotent differentiation. This study was undertaken to investigate the ability of MDSCs that were retrovirally transduced to express bone morphogenetic protein 4 (BMP-4) to differentiate into chondrocytes in vitro and in vivo and enhance articular cartilage repair.
  
  
  METHODS
  Using monolayer and micromass pellet culture systems, we evaluated the in vitro chondrogenic differentiation of LacZ- and BMP-4-transduced MDSCs with or without transforming growth factor beta1 (TGFbeta1) stimulation. We used a nude rat model of a full-thickness articular cartilage defect to assess the duration of LacZ transgene expression and evaluate the ability of transplanted cells to acquire a chondrocytic phenotype. We evaluated cartilage repair macroscopically and histologically 4, 8, 12, and 24 weeks after surgery, and performed histologic grading of the repaired tissues.
  
  
  RESULTS
  BMP-4-expressing MDSCs acquired a chondrocytic phenotype in vitro more effectively than did MDSCs expressing only LacZ; the addition of TGFbeta1 did not alter chondrogenic differentiation of the BMP-4-transduced MDSCs. LacZ expression within the repaired tissue continued for up to 12 weeks. Four weeks after surgery, we detected donor cells that coexpressed beta-galactosidase and type II collagen. Histologic scoring of the defect sites 24 weeks after transplantation revealed significantly better cartilage repair in animals that received BMP-4-transduced MDSCs than in those that received MDSCs expressing only LacZ.
  
  
  CONCLUSIONS
  Local delivery of BMP-4 by genetically engineered MDSCs enhanced chondrogenesis and significantly improved articular cartilage repair in rats.
authors.affiliation: Children's Hospital of Pittsburgh and University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Kuroda
authors.forename: Arvydas
authors.initials: A
authors.lastname: Usas
authors.forename: Seiji
authors.initials: S
authors.lastname: Kubo
authors.forename: Karin
authors.initials: K
authors.lastname: Corsi
authors.forename: Hairong
authors.initials: H
authors.lastname: Peng
authors.forename: Tim
authors.initials: T
authors.lastname: Rose
authors.forename: James
authors.initials: J
authors.lastname: Cummins
authors.forename: Freddie H
authors.initials: FH
authors.lastname: Fu
authors.forename: Johnny
authors.initials: J
authors.lastname: Huard
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D002358:Cartilage, Articular / Q000254:growth & development* / Q000293:injuries / Q000473:pathology; D002454:Cell Differentiation; D019902:Chondrocytes / Q000166:cytology / Q000378:metabolism; D020219:Chondrogenesis / Q000502:physiology*; D024043:Collagen Type II / Q000378:metabolism; D015316:Genetic Therapy; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D018482:Muscle, Skeletal / Q000166:cytology* / Q000378:metabolism; D011509:Proteoglycans / Q000378:metabolism; D051381:Rats; D011923:Rats, Nude; D012038:Regeneration / Q000502:physiology*; D014161:Transduction, Genetic / Q000379:methods; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D015415:Biomarkers; C525810:Bmp4 protein, mouse; C525811:Bmp4 protein, rat; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D024043:Collagen Type II; D011509:Proteoglycans; D001616:beta-Galactosidase