title: Type X collagen synthesis in human osteoarthritic cartilage. Indication of chondrocyte hypertrophy.
abstract: OBJECTIVE
  To investigate the appearance of hypertrophic chondrocytes in osteoarthritic (OA) cartilage, using type X collagen as a specific marker.
  
  
  METHODS
  The biosynthesis of type X collagen was examined by metabolic labeling of freshly isolated articular chondrocytes with 3H-proline, immunoprecipitation, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the synthesized collagens. Extracellular deposition of types X and II collagen was analyzed immunohistochemically.
  
  
  RESULTS
  Immunostaining revealed an irregular distribution of type X collagen, which was localized around chondrocyte clusters in fibrillated OA cartilage, but was absent from the noncalcified region of normal articular cartilage. Freshly isolated OA chondrocytes synthesized predominantly type X collagen, while control chondrocytes synthesized mostly type II collagen.
  
  
  CONCLUSIONS
  Our findings indicate focal premature chondrocyte differentiation to hypertrophic cells in OA cartilage.
authors.affiliation: Max-Planck-Society, Department of Orthopaedics, Waldkrankenhaus St. Marien, Erlangen, Federal Republic of Germany.
authors.forename: K
authors.initials: K
authors.lastname: von der Mark
authors.forename: T
authors.initials: T
authors.lastname: Kirsch
authors.forename: A
authors.initials: A
authors.lastname: Nerlich
authors.forename: A
authors.initials: A
authors.lastname: Kuss
authors.forename: G
authors.initials: G
authors.lastname: Weseloh
authors.forename: K
authors.initials: K
authors.lastname: Glückert
authors.forename: H
authors.initials: H
authors.lastname: Stöss
mesh_terms: D000328:Adult; D000368:Aged; D002358:Cartilage, Articular / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology*; D002478:Cells, Cultured; D003094:Collagen / Q000096:biosynthesis* / Q000737:chemistry; D005260:Female; D006801:Humans; D006984:Hypertrophy; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000378:metabolism*; D012016:Reference Values
chemical_list: D003094:Collagen