title: Sustained transgene expression in cartilage defects in vivo after transplantation of articular chondrocytes modified by lipid-mediated gene transfer in a gel suspension delivery system.
abstract: BACKGROUND
  Genetically modified chondrocytes may be able to modulate articular cartilage repair. To date, transplantation of modified chondrocytes into cartilage defects has been restricted to viral vectors. We tested the hypothesis that a recombinant gene can be delivered to sites of cartilage damage in vivo using chondrocytes transfected by a lipid-mediated gene transfer method.
  
  
  METHODS
  Isolated lapine articular chondrocytes were transfected with an expression plasmid vector carrying the P. pyralis luciferase gene using the reagent FuGENE 6. Transfected chondrocytes were encapsulated in alginate spheres and implanted into osteochondral defects in the knee joints of rabbits.
  
  
  RESULTS
  In vitro, luciferase activity in pCMVLuc-transfected spheres showed an early peak at day 2 post-transfection and remained elevated at day 32, the longest time point evaluated. The number of viable chondrocytes in non-transfected and transfected spheres increased over the period of cultivation. In vivo, luciferase activity was maximal at day 5 post-transfection, declined by day 16, but was still present at day 32. On histological analysis, the alginate-chondrocyte spheres filled the cartilage defects and were surrounded by a fibrous repair tissue composed of spindle-shaped cells.
  
  
  CONCLUSIONS
  These data demonstrate the successful introduction of articular chondrocytes modified by lipid-mediated gene transfer in a gel suspension delivery system into osteochondral defects and the sustained expression of the transgene in vivo. This method may be used to define the effects of genes involved in cartilage repair and may provide alternative treatments for articular cartilage defects.
authors.affiliation: Laboratory for Experimental Orthopaedics, Department of Orthopaedic Surgery, Saarland University Medical Center, Homburg, Germany. hmad@hotmail.com
authors.forename: Henning
authors.initials: H
authors.lastname: Madry
authors.forename: Magali
authors.initials: M
authors.lastname: Cucchiarini
authors.forename: Ute
authors.initials: U
authors.lastname: Stein
authors.forename: Klaus
authors.initials: K
authors.lastname: Remberger
authors.forename: Michael D
authors.initials: MD
authors.lastname: Menger
authors.forename: Dieter
authors.initials: D
authors.lastname: Kohn
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Trippel
mesh_terms: D000464:Alginates / Q000008:administration & dosage*; D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology* / Q000293:injuries* / Q000648:ultrastructure; D017690:Cell Transplantation / Q000379:methods*; D019902:Chondrocytes / Q000637:transplantation*; D005782:Gels; D005786:Gene Expression Regulation; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D008055:Lipids; D008156:Luciferases / Q000096:biosynthesis / Q000235:genetics; D008863:Microspheres; D010957:Plasmids; D011817:Rabbits; D013535:Suspensions; D013997:Time Factors; D014162:Transfection; D019076:Transgenes
chemical_list: D000464:Alginates; C411955:FuGene; D005782:Gels; D008055:Lipids; D013535:Suspensions; D008156:Luciferases