title: Short-term menatetrenone therapy increases gamma-carboxylation of osteocalcin with a moderate increase of bone turnover in postmenopausal osteoporosis: a randomized prospective study.
abstract: The effect of vitamin K(2) (menatetrenone) on bone turnover was investigated in postmenopausal patients with osteoporosis. A 6-month open-label, randomized prospective study was conducted in 109 patients. The control group (n = 53) received calcium aspartate (133.8 mg of elemental calcium daily), while the menatetrenone group (n = 56) received 45 mg of menatetrenone daily for 6 months. Serum and urinary levels of bone turnover markers were monitored. The serum level of undercarboxylated osteocalcin (uc-OC) was significantly lower (P < 0.001) in the menatetrenone group than in the control group (at 1 month), while there was a higher level of osteocalcin containing gamma-carboxylated glutamic acid (Gla-OC) in the menatetrenone group than the control group (P = 0.018). Significant differences of uc-OC and Gla-OC between the two groups were observed from 1 month onward. In addition, a higher level of intact osteocalcin was found in the menatetrenone group compared with the control group after 6 months (P = 0.006). Assessment of bone resorption markers showed that menatetrenone therapy was associated with significantly higher urinary N-telopeptide of type I collagen (NTX) excretion compared with the control group after 6 months, while there was no significant difference of urinary deoxypyridinoline excretion between the two groups. In conclusion, one month of menatetrenone therapy enhanced the secretion and gamma-carboxylation of osteocalcin, while urinary NTX excretion was increased after 6 months of treatment. Further investigations are required to determine whether the effects of menatetrenone on bone turnover are associated with fracture prevention.
authors.affiliation: Research Institute and Practice for Involutional Disease, 1610-1 Meisei, Misato, Azumino, Nagano 399-8101, Japan. ripid@fc4.so-net.ne.jp
authors.forename: Masataka
authors.initials: M
authors.lastname: Shiraki
authors.forename: Akira
authors.initials: A
authors.lastname: Itabashi
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D015519:Bone Density / Q000187:drug effects; D016723:Bone Remodeling / Q000187:drug effects; D002118:Calcium / Q000652:urine; D005260:Female; D006490:Hemostatics / Q000009:adverse effects / Q000627:therapeutic use*; D006728:Hormones / Q000378:metabolism; D006801:Humans; D008159:Lumbar Vertebrae / Q000187:drug effects / Q000503:physiopathology; D015675:Osteocalcin / Q000097:blood / Q000378:metabolism*; D015663:Osteoporosis, Postmenopausal / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology*; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D013997:Time Factors; D016896:Treatment Outcome; D024482:Vitamin K 2 / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D015415:Biomarkers; D006490:Hemostatics; D006728:Hormones; D015675:Osteocalcin; D024482:Vitamin K 2; C030814:menatetrenone; D002118:Calcium