title: Experimental hyperhomocysteinemia disturbs bone metabolism in rats.
abstract: OBJECTIVE
  To investigate whether experimental hyperhomocysteinemia (HHCY) can induce adverse changes in bone metabolism.
  
  
  METHODS
  Blood and urine samples were collected from rats fed with a methionine-enriched diet (HHCY, n = 18) or an isocaloric control diet (control, n = 10) for 12 weeks. Biochemical bone turnover markers (osteocalcin, hydroxyproline, N-terminal collagen I telopeptides and homocysteine (HCY), folate and vitamin B12) were measured. Whole body bone mineral density (BMD) was assessed by dual energy X-ray absorptiometry.
  
  
  RESULTS
  HCY was significantly higher in HHCY than in control rats (16.2 versus 3.2 micromol/L; p = 0.0006). Bone resorption parameters hydroxyproline (1.60 +/- 0.6 versus 0.85 +/- 0.4; p<0.05) and N-terminal collagen I telopeptides (150.8 +/- 78 versus 48.1 +/- 26 nmol/L BCE; p<0.05) increased, whereas bone formation marker osteocalcin (9.01 +/- 3.8 versus 15.07 +/- 4.2 ng/mL; p<0.05) decreased in HHCY compared to control rats. The relation N-terminal collagen I telopeptides/osteocalcin significantly increased in HHCY compared to control rats (13.14 +/- 3.1 versus 4.14 +/- 1.9). BMD measurement did not reveal any differences between groups.
  
  
  CONCLUSIONS
  These findings demonstrate a significant modification of bone turnover in HHCY rats. The relation between bone resorption and formation indicates a shift toward bone resorption, which might be a plausible explanation for the relation between HHCY and fracture risk.
authors.affiliation: Medical Faculty, Central Laboratory Biochemistry Unit, Akdeniz University, Antalya, Turkey. ozdem@akdeniz.edu.tr
authors.forename: S
authors.initials: S
authors.lastname: Ozdem
authors.forename: S
authors.initials: S
authors.lastname: Samanci
authors.forename: A
authors.initials: A
authors.lastname: Tasatargil
authors.forename: A
authors.initials: A
authors.lastname: Yildiz
authors.forename: G
authors.initials: G
authors.lastname: Sadan
authors.forename: L
authors.initials: L
authors.lastname: Donmez
authors.forename: M
authors.initials: M
authors.lastname: Herrmann
mesh_terms: D000818:Animals; D001835:Body Weight; D015519:Bone Density; D001862:Bone Resorption / Q000209:etiology / Q000378:metabolism; D001842:Bone and Bones / Q000378:metabolism*; D024042:Collagen Type I / Q000652:urine; D003401:Creatine / Q000652:urine; D005260:Female; D005492:Folic Acid / Q000097:blood; D006710:Homocysteine / Q000097:blood; D006909:Hydroxyproline / Q000652:urine; D020138:Hyperhomocysteinemia / Q000139:chemically induced / Q000150:complications / Q000503:physiopathology*; D008715:Methionine / Q000008:administration & dosage / Q000097:blood; D015675:Osteocalcin / Q000097:blood; D010012:Osteogenesis / Q000502:physiology; D010455:Peptides / Q000652:urine; D051381:Rats; D017208:Rats, Wistar; D014805:Vitamin B 12 / Q000097:blood
chemical_list: D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D006710:Homocysteine; D015675:Osteocalcin; D005492:Folic Acid; D008715:Methionine; D003401:Creatine; D014805:Vitamin B 12; D006909:Hydroxyproline