title: Genetic differences in the osteogenic differentiation potency according to the classification of ossification of the posterior longitudinal ligament of the cervical spine.
abstract: METHODS
  We categorized the four types of ossification of the posterior longitudinal ligament (OPLL) of the cervical spine into two groups. We biochemically investigated the genetic differences in the osteogenic differentiation potency between the two groups.
  
  
  OBJECTIVE
  To investigate the genetic differences in the osteogenic differentiation potency according to the OPLL classification.
  
  
  BACKGROUND
  Clinical studies on OPLL have revealed that the risk of progression of the ossification area is greatest for continuous and mixed type OPLL. However, until now, these four types of OPLL have been studied as a single condition.
  
  
  METHODS
  We categorized the four types of OPLL into the OPLL continuous (continuous or mixed type) and OPLL segmental groups (segmental or circumscribed type). Paraspinal ligaments were aseptically obtained from OPLL patients during surgery. The fibroblast-like cells that migrated from the explants were used for experiments. The cells were placed in a 60-mm culture dishes for total ribonucleic acid preparation and 12 well microplates for alkaline phosphatase (ALP) activity staining. After cultures reached confluence, the cells were cultured in osteogenic medium. The messenger ribonucleic acid expression of bone morphogenetic protein-2 (BMP-2), osterix, tumor necrosis factor-α-stimulated gene-6, and ALP was analyzed by quantitative real time-polymerase chain reaction. Osteogenic differentiation of fibroblast-like cells was determined by histochemically detecting ALP production.
  
  
  RESULTS
  After osteogenic induction, BMP-2 expression increased in the OPLL continuous and segmental groups. Osterix expression increased in the OPLL continuous group only. Tumor necrosis factor-α-stimulated gene-6 expression was suppressed in the OPLL continuous and segmental groups. ALP expression as well as ALP activity staining was higher in the OPLL continuous group than in the OPLL segmental group. CONCLUSION.: The study revealed genetic differences in the osteogenic differentiation potency between the OPLL continuous and segmental groups. We propose to distinguish OPLL continuous group from segmental group in biochemical studies on OPLL.
authors.affiliation: Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kudo
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Furukawa
authors.forename: Toru
authors.initials: T
authors.lastname: Yokoyama
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ono
authors.forename: Takuya
authors.initials: T
authors.lastname: Numasawa
authors.forename: Kanichiro
authors.initials: K
authors.lastname: Wada
authors.forename: Sunao
authors.initials: S
authors.lastname: Tanaka
authors.forename: Toru
authors.initials: T
authors.lastname: Asari
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Ueyama
authors.forename: Shigeru
authors.initials: S
authors.lastname: Motomura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Toh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002454:Cell Differentiation / Q000235:genetics*; D002478:Cells, Cultured; D002574:Cervical Vertebrae / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017887:Ossification of Posterior Longitudinal Ligament / Q000145:classification* / Q000473:pathology*; D010012:Osteogenesis / Q000235:genetics*; D012727:Sex Characteristics