title: Osteogenic protein-1 promotes the formation of tissue-engineered cartilage using the alginate-recovered-chondrocyte method.
abstract: OBJECTIVE
  This study examined the effects of a growth factor, recombinant human osteogenic protein-1 (rhOP-1), on the formation of tissue-engineered cartilaginous tissue by adult bovine articular chondrocytes using the alginate-recovered-chondrocyte (ARC) method.
  
  
  METHODS
  To ascertain if rhOP-1 enhances the formation of the cell-associated matrix (CM) and the characteristics of CM formation, bovine articular chondrocytes were first cultured for up to 14 days in alginate beads in medium supplemented with serum, with or without rhOP-1. Then, the recovered chondrocytes and their associated CM were resuspended in medium, with or without OP-1, seeded onto culture inserts, and incubated for an additional 14 days. The fabricated ARC tissues were subjected to biochemical and histological analyses.
  
  
  RESULTS
  The addition of rhOP-1 to the medium in the alginate bead culture step resulted in an increased accumulation of both proteoglycan (PG) and collagen, with a ratio of PG to collagen that was higher than that found in native adult cartilage. The addition of rhOP-1 in the second step had a similar stimulatory effect during 14 days of culture. Histological examination of the tissue formed under all conditions revealed a cartilage-like matrix, stained strongly by toluidine blue. The thickness of the tissues obtained from culture conditions that included the addition of rhOP-1 was four times greater than that of the tissues cultured without rhOP-1.
  
  
  CONCLUSIONS
  Using the ARC method, rhOP-1 enhanced the formation of matrix and generated a voluminous tissue-engineered cartilaginous construct. These characteristics may be beneficial in generating constructs that can cover large defects.
authors.affiliation: Department of Orthopedic Surgery, Rush Medical College at Rush University Medical Center, 1653 W. Congress Parkway, Chicago, IL 60612, USA. kmasuda@rush.edu
authors.forename: K
authors.initials: K
authors.lastname: Masuda
authors.forename: B E
authors.initials: BE
authors.lastname: Pfister
authors.forename: R L
authors.initials: RL
authors.lastname: Sah
authors.forename: E J-M A
authors.initials: EJ
authors.lastname: Thonar
mesh_terms: D000464:Alginates; D000818:Animals; D001672:Biocompatible Materials; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D002358:Cartilage, Articular / Q000737:chemistry / Q000166:cytology*; D002417:Cattle; D018929:Cell Culture Techniques / Q000379:methods; D019902:Chondrocytes / Q000166:cytology*; D003094:Collagen / Q000737:chemistry; D005109:Extracellular Matrix / Q000737:chemistry; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D011509:Proteoglycans / Q000737:chemistry; D023822:Tissue Engineering / Q000379:methods*; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
chemical_list: D000464:Alginates; C525819:BMP7 protein, human; D001672:Biocompatible Materials; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins; D006603:Hexuronic Acids; D011509:Proteoglycans; D016212:Transforming Growth Factor beta; D020723:Glucuronic Acid; D003094:Collagen