title: High serum levels of menatetrenone in male patients with ossification of the posterior longitudinal ligament.
abstract: METHODS
  This work was performed to investigate the role of vitamin K (VK) in the pathogenesis of ossification of posterior longitudinal ligament (OPLL), by analyzing the biochemical markers of the blood samples of OPLL patients and responses of ligament cells derived from OPLL lesion to VK2.
  
  
  OBJECTIVE
  The pathogenesis of OPLL, classified as a form of diffuse idiopathic skeletal hyperostosis, is still unclear. In this study, we investigated the role of menaquinone (VK2) in patients with OPLL (OPLL patients) and the effects of VK2 on ligament cells isolated from OPLL lesion.
  
  
  METHODS
  Serum levels of intact osteocalcin, glu-osteocalcin, MK-4, -7 (VK2 variants) and other minerals in spot blood samples were measured in 24 OPLL patients and in 24 age-matched control patients (non-OPLL patients). The cultured cells isolated from an OPLL patient were treated with MK-4. Alkaline phosphatase (Al-p) activity and osteocalcin release were measured after 2 weeks of culture.
  
  
  RESULTS
  In the clinical study, the serum MK-4 in male OPLL patients was significantly higher than that in male non-OPLL patients. However, among female patients, the difference was not significant. Although the serum osteocalcin in females was significantly higher than that in males, there was no significant difference between the OPLL and non-OPLL groups. In in vitro study, MK-4 did not increase Al-p activity in the ligament cells isolated from nonossified region of OPLL patient. Osteoblastic activity of the cultured cells was not stimulated by MK-4.
  
  
  CONCLUSIONS
  From these results and previous reports, we propose the possibility of the impediment in VK2 metabolism in OPLL patients. The results also implicate the gender tendency in OPLL, because the difference of serum level of MK-4 in OPLL patients was significant only in male.
authors.affiliation: Department of Orthopaedic Surgery, Osaka City University Medical School, Osaka, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Yamada
authors.forename: Kentaro
authors.initials: K
authors.lastname: Inui
authors.forename: Masahiro
authors.initials: M
authors.lastname: Iwamoto
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nakamura
authors.forename: Tadao
authors.initials: T
authors.lastname: Tsujio
authors.forename: Sadahiko
authors.initials: S
authors.lastname: Konishi
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Ito
authors.forename: Kunio
authors.initials: K
authors.lastname: Takaoka
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Koike
mesh_terms: D000368:Aged; D000469:Alkaline Phosphatase / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D017846:Longitudinal Ligaments / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D017887:Ossification of Posterior Longitudinal Ligament / Q000097:blood* / Q000473:pathology; D015675:Osteocalcin / Q000097:blood; D012737:Sex Factors; D013997:Time Factors; D024482:Vitamin K 2 / Q000031:analogs & derivatives* / Q000097:blood* / Q000494:pharmacology
chemical_list: D015675:Osteocalcin; D024482:Vitamin K 2; C030814:menatetrenone; D000469:Alkaline Phosphatase