title: Human telomerase reverse transcriptase and glucose-regulated protein 78 increase the life span of articular chondrocytes and their repair potential.
abstract: BACKGROUND
  Like all mammalian cells, normal adult chondrocytes have a limited replicative life span, which decreases with age. To facilitate the therapeutic use of chondrocytes from older donors, a method is needed to prolong their life span.
  
  
  METHODS
  We transfected chondrocytes with hTERT or GRP78 and cultured them in a 3-dimensional atelocollagen honeycomb-shaped scaffold with a membrane seal. Then, we measured the amount of nuclear DNA and glycosaminoglycans (GAGs) and the expression level of type II collagen as markers of cell proliferation and extracellular matrix formation, respectively, in these cultures. In addition, we allografted this tissue-engineered cartilage into osteochondral defects in old rabbits to assess their repair activity in vivo.
  
  
  RESULTS
  Our results showed different degrees of differentiation in terms of GAG content between chondrocytes from old and young rabbits. Chondrocytes that were cotransfected with hTERT and GRP78 showed higher cellular proliferation and expression of type II collagen than those of nontransfected chondrocytes, regardless of the age of the cartilage donor. In addition, the in vitro growth rates of hTERT- or GRP78-transfected chondrocytes were higher than those of nontransfected chondrocytes, regardless of donor age. In vivo, the tissue-engineered cartilage implants exhibited strong repairing activity, maintained a chondrocyte-specific phenotype, and produced extracellular matrix components.
  
  
  CONCLUSIONS
  Focal gene delivery to aged articular chondrocytes exhibited strong repairing activity and may be therapeutically useful for articular cartilage regeneration.
authors.affiliation: Department of Orthopaedic Surgery, Surgical Science, Tokai University School of Medicine, Isehara, Kanagawa, Japan. sato-m@is.icc.u-tokai.ac.jp
authors.forename: Masato
authors.initials: M
authors.lastname: Sato
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shin-ya
authors.forename: Jeong Ik
authors.initials: JI
authors.lastname: Lee
authors.forename: Miya
authors.initials: M
authors.lastname: Ishihara
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nagai
authors.forename: Nagatoshi
authors.initials: N
authors.lastname: Kaneshiro
authors.forename: Genya
authors.initials: G
authors.lastname: Mitani
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Tahara
authors.forename: Joji
authors.initials: J
authors.lastname: Mochida
mesh_terms: D000818:Animals; D002357:Cartilage Diseases / Q000201:enzymology* / Q000473:pathology / Q000601:surgery; D002358:Cartilage, Articular / Q000201:enzymology* / Q000473:pathology / Q000601:surgery; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D019902:Chondrocytes / Q000201:enzymology* / Q000473:pathology / Q000637:transplantation; D020219:Chondrogenesis; D003094:Collagen; D024043:Collagen Type II / Q000235:genetics / Q000378:metabolism; D004261:DNA Replication; D004195:Disease Models, Animal; D000091342:Endoplasmic Reticulum Chaperone BiP; D005260:Female; D006025:Glycosaminoglycans / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008297:Male; D010329:Patella / Q000201:enzymology* / Q000473:pathology / Q000601:surgery; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D012038:Regeneration; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D046509:Tissue Culture Techniques; D054457:Tissue Scaffolds; D014162:Transfection
chemical_list: D024043:Collagen Type II; D000091342:Endoplasmic Reticulum Chaperone BiP; D006025:Glycosaminoglycans; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D012333:RNA, Messenger; C059821:atelocollagen; D003094:Collagen; C509186:TERT protein, human; D019098:Telomerase