title: Asporin and transforming growth factor-beta gene expression in osteoblasts from subchondral bone and osteophytes in osteoarthritis.
abstract: BACKGROUND
  To clarify the significance of subchondral bone and osteophytes in the pathology of osteoarthritis (OA), we investigated the expression of asporin (ASPN), transforming growth factor-beta1 (TGF-beta1), TGF-beta2, TGF-beta3, and runt-related transcription factor-2 (Runx2) genes involved in bone metabolism.
  
  
  METHODS
  Osteoblasts were isolated from 19 patients diagnosed with knee OA and from 4 patients diagnosed with femoral neck fracture. Osteoblast expression of mRNA encoding ASPN, TGF-beta1, TGF-beta2, TGF-beta3, and Runx2 was analyzed using real-time RT-PCR.
  
  
  RESULTS
  Expression of ASPN, TGF-beta1, and TGF-beta3 mRNA in the subchondral bone and osteophytes of OA patients increased compared with that of non-OA patients. The ratio of ASPN to TGF-beta1 mRNA in patients with severe cartilage damage was higher than that in patients with mild cartilage damage.
  
  
  CONCLUSIONS
  The increased ratio of ASPN mRNA to TGF-beta1 mRNA in patients with severe relative to mild cartilage damage indicates that increased ASPN mRNA expression was significantly associated with the severity of cartilage degeneration. This finding suggests that ASPN may regulate TGF-beta1-mediated factors in the development of OA, which may provide clues as to the underlying pathology of OA.
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Sakao
authors.forename: Kenji A
authors.initials: KA
authors.lastname: Takahashi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Arai
authors.forename: Masazumi
authors.initials: M
authors.lastname: Saito
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Honjyo
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Hiraoka
authors.forename: Tsunao
authors.initials: T
authors.lastname: Kishida
authors.forename: Osam
authors.initials: O
authors.lastname: Mazda
authors.forename: Jiro
authors.initials: J
authors.lastname: Imanishi
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Kubo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002478:Cells, Cultured; D016326:Extracellular Matrix Proteins / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005663:Furans; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D020370:Osteoarthritis, Knee / Q000235:genetics* / Q000378:metabolism; D010006:Osteoblasts / Q000378:metabolism*; D054850:Osteophyte / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D012720:Severity of Illness Index; D013876:Thiophenes; D053773:Transforming Growth Factor beta1 / Q000235:genetics* / Q000378:metabolism; D053781:Transforming Growth Factor beta2 / Q000235:genetics / Q000378:metabolism; D053782:Transforming Growth Factor beta3 / Q000235:genetics / Q000378:metabolism
chemical_list: C516387:3,4-bis-(2,4,5-trimethyl-thiophen-3-yl)furan-2,5-dione; C439889:ASPN protein, human; D016326:Extracellular Matrix Proteins; D005663:Furans; D012333:RNA, Messenger; D013876:Thiophenes; D053773:Transforming Growth Factor beta1; D053781:Transforming Growth Factor beta2; D053782:Transforming Growth Factor beta3