title: Effect of self-assembling peptide, chondrogenic factors, and bone marrow-derived stromal cells on osteochondral repair.
abstract: OBJECTIVE
  The goal of this study was to test the ability of an injectable self-assembling peptide (KLD) hydrogel with or without chondrogenic factors (CF) and allogeneic bone marrow stromal cells (BMSCs) to stimulate cartilage regeneration in a full-thickness, critically-sized, rabbit cartilage defect model in vivo. We used CF treatments to test the hypotheses that CF would stimulate chondrogenesis and matrix production by cells migrating into acellular KLD (KLD+CF) or by BMSCs delivered in KLD (KLD+CF+BMSCs).
  
  
  METHODS
  Three groups were tested against contralateral untreated controls: KLD, KLD+CF, and KLD+CF+BMSCs, n=6-7. Transforming growth factor-β1 (TGF-β1), dexamethasone, and insulin-like growth factor-1 (IGF-1) were used as CF pre-mixed with KLD and BMSCs before injection. Evaluations included gross, histological, immunohistochemical and radiographic analyses.
  
  
  RESULTS
  KLD without CF or BMSCs showed the greatest repair after 12 weeks with significantly higher Safranin-O, collagen II immunostaining, and cumulative histology scores than untreated contralateral controls. KLD+CF resulted in significantly higher aggrecan immunostaining than untreated contralateral controls. Including allogeneic BMSCs+CF markedly reduced the quality of repair and increased osteophyte formation compared to KLD-alone.
  
  
  CONCLUSIONS
  These data show that KLD can fill full-thickness osteochondral defects in situ and improve cartilage repair as shown by Safranin-O, collagen II immunostaining, and cumulative histology. In this small animal model, the full-thickness critically-sized defect provided access to the marrow, similar in concept to abrasion arthroplasty or spongialization in large animal models, and suggests that combining KLD with these techniques may improve current practice.
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Miller
authors.forename: A J
authors.initials: AJ
authors.lastname: Grodzinsky
authors.forename: E J
authors.initials: EJ
authors.lastname: Vanderploeg
authors.forename: C
authors.initials: C
authors.lastname: Lee
authors.forename: D J
authors.initials: DJ
authors.lastname: Ferris
authors.forename: M F
authors.initials: MF
authors.lastname: Barrett
authors.forename: J D
authors.initials: JD
authors.lastname: Kisiday
authors.forename: D D
authors.initials: DD
authors.lastname: Frisbie
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000293:injuries* / Q000473:pathology / Q000502:physiology; D020219:Chondrogenesis / Q000187:drug effects / Q000502:physiology*; D003907:Dexamethasone / Q000494:pharmacology; D005260:Female; D020100:Hydrogels; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D045164:Mesenchymal Stem Cell Transplantation / Q000379:methods*; D011817:Rabbits; D011859:Radiography; D012038:Regeneration / Q000187:drug effects; D013583:Synovial Membrane / Q000473:pathology; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology
chemical_list: D020100:Hydrogels; D053773:Transforming Growth Factor beta1; D007334:Insulin-Like Growth Factor I; D003907:Dexamethasone