title: Cell-based tissue engineering for the intervertebral disc: in vitro studies of human disc cell gene expression and matrix production within selected cell carriers.
abstract: BACKGROUND
  Little is known about how disc cells attach, proliferate and form extracellular matrix (ECM) within carrier materials. Such information is needed to help formulate criteria for successful cell-carrier interactions in tissue engineering.
  
  
  OBJECTIVE
  To compare proliferation, ECM production and gene expression in annulus cells cultured in a variety of cell carrier materials with potential application in tissue engineering of the disc.
  
  
  METHODS
  Human intervertebral disc cells from the annulus were used in a prospective study of proliferation, ECM production and gene expression within selected cell carriers.
  
  
  METHODS
  Annulus cells from discs of 29 individuals were tested in collagen sponge, collagen gel, agarose, alginate or fibrin gel formulations. In situ hybridization assessed ECM gene expression of Types I and II collagen, aggrecan and chondroitin-6 sulfotransferase. Cell proliferation, cell shape, attachment and ECM production were evaluated.
  
  
  RESULTS
  Collagen sponges provided the best microenvironment for disc cell ECM production and gene expression. Although collagen gels often could support good cell growth, such constructs did not result in either abundant ECM production or ECM gene expression, as shown by in situ hybridization. Growth and ECM production and gene expression in alginate, agarose and fibrin microenvironments were inferior.
  
  
  CONCLUSIONS
  Tissue engineering techniques open new therapeutic possibilities for use of autologous disc cells, but fundamental questions on how these cells interact with cell carriers are unexplored. Results provide novel data on disc cell gene expression within diverse microenvironments. The collagen sponge proved to be a superior microenvironment.
authors.affiliation: Department of Orthopaedic Surgery, Carolinas Medical Center, 1542 Garden Terrace, Charlotte, NC 28203, USA. hgruber@carolinas.org
authors.forename: Helen E
authors.initials: HE
authors.lastname: Gruber
authors.forename: Kelly
authors.initials: K
authors.lastname: Leslie
authors.forename: Jane
authors.initials: J
authors.lastname: Ingram
authors.forename: H James
authors.initials: HJ
authors.lastname: Norton
authors.forename: Edward N
authors.initials: EN
authors.lastname: Hanley
mesh_terms: D020341:Absorbable Implants; D000328:Adult; D000368:Aged; D001672:Biocompatible Materials; D018929:Cell Culture Techniques / Q000379:methods; D002455:Cell Division; D002478:Cells, Cultured; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis* / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D006801:Humans; D017403:In Situ Hybridization; D007403:Intervertebral Disc / Q000166:cytology* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D023822:Tissue Engineering
chemical_list: D001672:Biocompatible Materials; D016326:Extracellular Matrix Proteins; D012333:RNA, Messenger