title: Topographic variation in redifferentiation capacity of chondrocytes in the adult human knee joint.
abstract: OBJECTIVE
  The aim of this study was to investigate the topographic variation in matrix production and cell density in the adult human knee joint. Additionally, we have examined the redifferentiation potential of chondrocytes expanded in vitro from the different locations.
  
  
  METHODS
  Full thickness cartilage-bone biopsies were harvested from seven separate anatomical locations of healthy knee joints from deceased adult human donors. Chondrocytes were isolated, expanded in vitro and redifferentiated in a pellet mass culture. Biochemical analysis of total collagen, proteoglycans and cellular content as well as histology and immunohistochemistry were performed on biopsies and pellets.
  
  
  RESULTS
  In the biochemical analysis of the biopsies, we found lower proteoglycan to collagen (GAG/HP) ratio in the non-weight bearing (NWB) areas compared to the weight bearing (WB) areas. The chondrocytes harvested from different locations in femur showed a significantly better attachment and proliferation ability as well as good post-expansion chondrogenic capacity in pellet mass culture compared with the cells harvested from tibia.
  
  
  CONCLUSIONS
  These results demonstrate that there are differences in extra cellular content within the adult human knee in respect to GAG/HP ratio. Additionally, the data show that clear differences between chondrocytes harvested from femur and tibia from healthy human knee joints exist and that the differences are not completely abolished during the process of de- and redifferentiation. These findings emphasize the importance of the understanding of topographic variation in articular cartilage biology when approaching new cartilage repair strategies.
authors.affiliation: Department of Clinical Chemistry and Transfusion Medicine, Sahlgrenska University Hospital, Göteborg University, Gothenburg, Sweden. hanna.stenhamre@medic.gu.se
authors.forename: H
authors.initials: H
authors.lastname: Stenhamre
authors.forename: K
authors.initials: K
authors.lastname: Slynarski
authors.forename: C
authors.initials: C
authors.lastname: Petrén
authors.forename: T
authors.initials: T
authors.lastname: Tallheden
authors.forename: A
authors.initials: A
authors.lastname: Lindahl
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000502:physiology*; D018929:Cell Culture Techniques / Q000379:methods; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation; D019902:Chondrocytes / Q000166:cytology*; D003094:Collagen / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism; D006801:Humans; D007719:Knee Joint / Q000166:cytology*; D011509:Proteoglycans / Q000378:metabolism*
chemical_list: D011509:Proteoglycans; D003094:Collagen