title: Development and remodeling of engineered cartilage-explant composites in vitro and in vivo.
abstract: OBJECTIVE
  Development and remodeling of engineered cartilage-explant composites were studied in vitro and in vivo.
  
  
  METHODS
  Individual and interactive effects of cell chondrogenic potential (primary or fifth passage bovine calf chondrocytes), scaffold degradation rate (hyaluronan benzyl ester or polyglycolic acid), and adjacent tissue cell activity and architecture (vital trabecular bone (VB), articular cartilage (AC), devitalized bone (DB) or digested cartilage (DC)) were evaluated over 8 weeks in vitro (bioreactor cultures) and in vivo (ectopic implants).
  
  
  RESULTS
  In vitro, significant effects of cell type on construct adhesive strength (P<0.001) and scaffold type on adhesive strength (P<0.001), modulus (P=0.014), glycosaminoglycans (GAG) (P<0.001), and collagen (P=0.039) were observed. Chondrogenesis was best when the scaffold degradation rate matched the extracellular matrix deposition rate. In vivo, adjacent tissue type affected adhesive strength (P<0.001), modulus (P<0.001), and GAG (P<0.001) such that 8-week values obtained for bone (VB and DB) were higher than for cartilage (AC). In the AC/construct group, chondrogenesis appeared attenuated in the region of the construct close to the AC. In contrast, in the VB/construct group, a 500 microm thick zone of mature hyaline-like cartilage formed at the interface, and signs of active remodeling were present in the bone that included osteoclastic and osteoblastic activity and trabecular rebuttressing; these features were not present in the DB group or in vitro.
  
  
  CONCLUSIONS
  Development and remodeling of composites based on engineered cartilage were mediated in vitro by cell chondrogenic potential and scaffold degradation rate, and in vivo by type of adjacent tissue and time.
authors: Division of Health Sciences and Technology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
authors: Enrico
authors: E
authors: Tognana
authors: Robert F
authors: RF
authors: Padera
authors: Fen
authors: F
authors: Chen
authors: Gordana
authors: G
authors: Vunjak-Novakovic
authors: Lisa E
authors: LE
authors: Freed
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D019149:Bioreactors; D016723:Bone Remodeling / Q000502:physiology*; D002358:Cartilage, Articular / Q000166:cytology / Q000502:physiology / Q000637:transplantation*; D002417:Cattle; D002448:Cell Adhesion / Q000502:physiology; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000637:transplantation*; D020219:Chondrogenesis / Q000502:physiology; D023822:Tissue Engineering / Q000379:methods*