title: Isolation and characterization of human articular chondrocytes from surgical waste after total knee arthroplasty (TKA).
abstract: BACKGROUND
  Cartilage tissue engineering is a fast-evolving field of biomedical engineering, in which the chondrocytes represent the most commonly used cell type. Since research in tissue engineering always consumes a lot of cells, simple and cheap isolation methods could form a powerful basis to boost such studies and enable their faster progress to the clinics. Isolated chondrocytes can be used for autologous chondrocyte implantation in cartilage repair, and are the base for valuable models to investigate cartilage phenotype preservation, as well as enable studies of molecular features, nature and scales of cellular responses to alterations in the cartilage tissue.
  
  
  METHODS
  Isolation and consequent cultivation of primary human adult articular chondrocytes from the surgical waste obtained during total knee arthroplasty (TKA) was performed. To evaluate the chondrogenic potential of the isolated cells, gene expression of collagen type 2 (COL2), collagen 1 (COL1) and aggrecan (ACAN) was evaluated. Immunocytochemical staining of all mentioned proteins was performed to evaluate chondrocyte specific production.
  
  
  RESULTS
  Cartilage specific gene expression of COL2 and ACAN has been shown that the proposed protocol leads to isolation of cells with a high chondrogenic potential, possibly even specific phenotype preservation up to the second passage. COL1 expression has confirmed the tendency of the isolated cells dedifferentiation into a fibroblast-like phenotype already in the second passage, which confirms previous findings that higher passages should be used with care in cartilage tissue engineering. To evaluate the effectiveness of our approach, immunocytochemical staining of the evaluated chondrocyte specific products was performed as well.
  
  
  CONCLUSIONS
  In this study, we developed a protocol for isolation and consequent cultivation of primary human adult articular chondrocytes with the desired phenotype from the surgical waste obtained during TKA. TKA is a common and very frequently performed orthopaedic surgery during which both femoral condyles are removed. The latter present the ideal source for a simple and relatively cheap isolation of chondrocytes as was confirmed in our study.
authors.affiliation: Department of Orthopaedics, University Medical Centre Maribor , Maribor , Slovenia.
authors.forename: Jakob
authors.initials: J
authors.lastname: Naranda
authors.affiliation: Institute of Biomedical Sciences, University of Maribor, Faculty of Medicine , Maribor , Slovenia.
authors.forename: Lidija
authors.initials: L
authors.lastname: Gradišnik
authors.affiliation: Center for Human Molecular Genetics and Pharmacogenomics, University of Maribor, Faculty of Medicine , Maribor , Slovenia.
authors.forename: Mario
authors.initials: M
authors.lastname: Gorenjak
authors.affiliation: Department of Orthopaedics, University Medical Centre Maribor , Maribor , Slovenia.
authors.forename: Matjaž
authors.initials: M
authors.lastname: Vogrin
authors.affiliation: Institute of Biomedical Sciences, University of Maribor, Faculty of Medicine , Maribor , Slovenia.
authors.forename: Uroš
authors.initials: U
authors.lastname: Maver
keywords: Aggrecan; Collagen 2; Gene expression; Human articular chondrocytes; Isolation protocol; Phenotype preservation; TKA; Total knee arthroplasty