title: Response of serum carboxylated and undercarboxylated osteocalcin to alendronate monotherapy and combined therapy with vitamin K2 in postmenopausal women.
abstract: Alendronate decreases the risk of femoral neck fracture by suppressing bone turnover, and also decreases the serum total osteocalcin level. A low serum carboxylated osteocalcin level or high undercarboxylated osteocalcin level could be risk factors for femoral neck fracture. Vitamin K mediates the carboxylation of osteocalcin, but the effect of alendronate therapy with or without vitamin K(2) supplementation remains unknown. Forty-eight postmenopausal women were enrolled in a 1-year prospective randomized trial and assigned to alendronate monotherapy (5 mg/day) (group A, n = 26) or vitamin K(2) (45 mg/day) plus alendronate (5 mg/day) (group AK, n = 22). Bone mineral density was measured by dual-energy X-ray absorptiometry at 0 and 12 months; bone turnover parameters were measured at 0, 3, and 12 months. Four patients discontinued alendronate therapy, and we analyzed the remaining 44 patients (23 in group A and 21 in group AK) who completed 1 year of treatment. Alendronate decreased undercarboxylated osteocalcin; carboxylated osteocalcin was not affected. Addition of vitamin K(2) enhanced the decrease of undercarboxylated osteocalcin levels and led to a greater increase of femoral neck bone mineral density. Alendronate monotherapy does not decrease carboxylation of osteocalcin, and combination of vitamin K(2) and alendronate brings further benefits on both osteocalcin carboxylation and BMD of femoral neck in postmenopausal women with osteoporosis.
authors.affiliation: Department of Orthopaedics, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Hirao
authors.forename: Jun
authors.initials: J
authors.lastname: Hashimoto
authors.forename: Wataru
authors.initials: W
authors.lastname: Ando
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ono
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
mesh_terms: D015055:1-Carboxyglutamic Acid / Q000097:blood; D000368:Aged; D019386:Alendronate / Q000627:therapeutic use*; D015519:Bone Density / Q000187:drug effects / Q000502:physiology; D050071:Bone Density Conservation Agents / Q000627:therapeutic use*; D002264:Carboxylic Acids / Q000097:blood*; D004359:Drug Therapy, Combination; D005260:Female; D005272:Femur Neck / Q000187:drug effects / Q000502:physiology; D006801:Humans; D015675:Osteocalcin / Q000097:blood*; D017698:Postmenopause / Q000187:drug effects*; D011446:Prospective Studies; D024482:Vitamin K 2 / Q000627:therapeutic use*
chemical_list: D050071:Bone Density Conservation Agents; D002264:Carboxylic Acids; D015675:Osteocalcin; D024482:Vitamin K 2; D015055:1-Carboxyglutamic Acid; D019386:Alendronate