title: Pronounced biomaterial dependency in cartilage regeneration using nonexpanded compared with expanded chondrocytes.
abstract: OBJECTIVE
  We aimed to investigate freshly isolated compared with culture-expanded chondrocytes with respect to early regenerative response, cytokine production and cartilage formation in response to four commonly used biomaterials.
  
  
  METHODS
  Chondrocytes were both directly and after expansion to passage 2, incorporated into four biomaterials: Polyactive™, Beriplast®, HyStem® and a type II collagen gel. Early cartilage matrix gene expression, cytokine production and glycosaminoglycan (GAG) and DNA content in response to these biomaterials were evaluated.
  
  
  RESULTS
  HyStem induced more GAG production, compared with all other biomaterials (p ≤ 0.001). Nonexpanded cells did not always produce more GAGs than expanded chondrocytes, as this was biomaterial-dependent. Cytokine production and early gene expression were not predictive for final regeneration.
  
  
  CONCLUSIONS
  For chondrocyte-based cartilage treatments, the biomaterial best supporting cartilage matrix production will depend on the chondrocyte differentiation state and cannot be predicted from early gene expression or cytokine profile.
authors.affiliation: Department of Orthopedics, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Anika I
authors.initials: AI
authors.lastname: Tsuchida
authors.forename: Joris Ej
authors.initials: JE
authors.lastname: Bekkers
authors.forename: Michiel
authors.initials: M
authors.lastname: Beekhuizen
authors.forename: Lucienne A
authors.initials: LA
authors.lastname: Vonk
authors.forename: Wouter Ja
authors.initials: WJ
authors.lastname: Dhert
authors.forename: Daniël Bf
authors.initials: DB
authors.lastname: Saris
authors.forename: Laura B
authors.initials: LB
authors.lastname: Creemers
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001672:Biocompatible Materials / Q000494:pharmacology*; D002356:Cartilage / Q000187:drug effects / Q000502:physiology*; D016923:Cell Death / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D005109:Extracellular Matrix / Q000187:drug effects / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008875:Middle Aged; D012038:Regeneration / Q000187:drug effects*; D054457:Tissue Scaffolds / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D016207:Cytokines; D007770:L-Lactate Dehydrogenase