title: Retaining zonal chondrocyte phenotype by means of novel growth environments.
abstract: The loss of phenotype in articular chondrocytes expanded in monolayer has been established as a possible contributor to the deficiencies associated with in vitro cartilage engineering and autologous cell transplantation procedures. We cultured zonal articular chondrocytes on tissue culture plastic, collagen II-coated polystyrene, and aggrecan-coated polystyrene in an effort to find a surface that can either prevent or slow the loss of phenotype. In addition, we encapsulated passaged cells in agarose to examine the effect of three-dimensional culture on redifferentiating zonal chondrocytes. We used real-time polymerase chain reaction to measure the relative gene expression levels of collagen I and II, aggrecan, and superficial zone protein over relevant passages (P0-P4). Results showed that tissue culture plastic and the collagen II-coated surface induced rapid loss of phenotype in zonal articular chondrocytes. The aggrecan-coated surface had a less detrimental effect on the chondrocytic phenotype of seeded cells, inducing gene expression characteristics comparable to those of agarose-encapsulated cells. Furthermore, when chondrocytes that had been previously passaged on a collagen II surface were placed on an aggrecan surface, the zonal cells showed a dramatic change in gene expression from fibroblastic to chondrocytic. These results indicate that a culture environment using aggrecan as a substratum or agarose as a scaffold is crucial to the development of phenotypically correct articular cartilage.
authors.affiliation: Department of Bioengineering, Rice University, Houston, Texas, USA.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Darling
authors.forename: Kyriacos A
authors.initials: KA
authors.lastname: Athanasiou
mesh_terms: D053674:Aggrecans; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D002358:Cartilage, Articular / Q000166:cytology* / Q000254:growth & development*; D018929:Cell Culture Techniques / Q000379:methods; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation; D048429:Cell Size; D002478:Cells, Cultured; D019902:Chondrocytes / Q000145:classification / Q000166:cytology* / Q000502:physiology*; D020219:Chondrogenesis / Q000502:physiology*; D016326:Extracellular Matrix Proteins / Q000737:chemistry*; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D006041:Goats; D037181:Lectins, C-Type; D008422:Materials Testing; D010641:Phenotype; D011509:Proteoglycans / Q000737:chemistry*; D012685:Sepharose / Q000737:chemistry*; D013499:Surface Properties; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D053674:Aggrecans; D001672:Biocompatible Materials; D016326:Extracellular Matrix Proteins; D037181:Lectins, C-Type; D011509:Proteoglycans; D012685:Sepharose