title: Effects of Hydrostatic Loading on a Self-Aggregating, Suspension Culture-Derived Cartilage Tissue Analog.
abstract: OBJECTIVE
  Many approaches are being taken to generate cartilage replacement materials. The goal of this study was to use a self-aggregating suspension culture model of chondrocytes with mechanical preconditioning.
  
  
  METHODS
  Our model differs from others in that it is based on a scaffold-less, self-aggregating culture model that produces a cartilage tissue analog that has been shown to share many similarities with the natural cartilage phenotype. Owing to the known loaded environment under which chondrocytes function in vivo, we hypothesized that applying force to the suspension culture-derived chondrocyte biomass would improve its cartilage-like characteristics and provide a new model for engineering cartilage tissue analogs.
  
  
  RESULTS
  In this study, we used a specialized hydrostatic pressure bioreactor system to apply mechanical forces during the growth phase to improve biochemical and biophysical properties of the biomaterial formed. We demonstrated that using this high-density suspension culture, a biomaterial more consistent with the hyaline cartilage phenotype was produced without any foreign material added. Unpassaged chondrocytes responded to a physiologically relevant hydrostatic load by significantly increasing gene expression of critical cartilage molecule collagen and aggrecan along with other cartilage relevant genes, CD44, perlecan, decorin, COMP, and iNOS.
  
  
  CONCLUSIONS
  This study describes a self-aggregating bioreactor model without foreign material or scaffold in which chondrocytes form a cartilage tissue analog with many features similar to native cartilage. This study represents a promising scaffold-less, methodological advancement in cartilage tissue engineering with potential translational applications to cartilage repair.
authors.affiliation: Department of Biological Sciences, University of Delaware, Newark, DE, USA.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Kraft
authors.affiliation: Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE, USA.
authors.forename: Changhoon
authors.initials: C
authors.lastname: Jeong
authors.affiliation: Department of Mechanical Engineering, University of Delaware, Newark, DE, USA.
authors.forename: John E
authors.initials: JE
authors.lastname: Novotny
authors.affiliation: Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Seacrist
authors.affiliation: Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE, USA.
authors.forename: Gilbert
authors.initials: G
authors.lastname: Chan
authors.affiliation: Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE, USA.
authors.forename: Marcin
authors.initials: M
authors.lastname: Domzalski
authors.affiliation: Department of Mechanical Engineering, University of Delaware, Newark, DE, USA.
authors.forename: Christina M
authors.initials: CM
authors.lastname: Turka
authors.affiliation: New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA, USA.
authors.forename: Dean W
authors.initials: DW
authors.lastname: Richardson
authors.affiliation: Department of Biological Sciences, University of Delaware, Newark, DE, USA.
authors.forename: George R
authors.initials: GR
authors.lastname: Dodge
keywords: bioengineering; cartilage repair; cartilage tissue engineering; hydrostatic loading