title: Teriparatide reduces bone microdamage accumulation in postmenopausal women previously treated with alendronate.
abstract: Suppression of bone turnover by bisphosphonates is associated with increased bone microdamage accumulation in animal models. Our objective was to study the effects of teriparatide treatment on changes in microdamage accumulation at the iliac crest in previously treatment-naïve patients or in those switched from alendronate to teriparatide. Sixty-six postmenopausal women with osteoporosis (mean age, 68.0 yr; and mean BMD T-score of -2.8 at lumbar spine and -1.7 at total hip; 62% with prevalent fractures) entered this prospective, nonrandomized study and started with 24-mo 20 microg/d subcutaneous teriparatide treatment in monotherapy: 38 patients stopped previous alendronate treatment (10 mg/d or 70 mg/wk for a mean duration of 63.6 mo) and switched to teriparatide, whereas 28 were previously treatment naïve. Thirty-one paired biopsies with two intact cortices were collected and analyzed for microstructure and microdamage accumulation at baseline and after 24 mo of teriparatide administration. After 24 mo of teriparatide treatment, crack density (Cr.Dn), crack surface density (Cr.S.Dn), and crack length (Cr.Le) were decreased in previously alendronate-treated patients, whereas only Cr.Le was reduced in former treatment-naïve patients. Patients with lower initial femoral neck BMD also showed a higher reduction of microdamage accumulation. Better bone microarchitecture correlated positively, whereas bone turnover markers and age did not correlate with reduced microdamage accumulation on teriparatide. In conclusion, teriparatide reduces microdamage accumulation in the iliac crest of patients previously treated with alendronate. There is insufficient evidence to suggest that age or bone turnover would be associated with this change.
authors.affiliation: Department of Internal Medicine, Division of Endocrinology and Nuclear Medicine, Medical University of Graz, Graz, Austria. harald.dobnig@medunigraz.at
authors.forename: Harald
authors.initials: H
authors.lastname: Dobnig
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Stepan
authors.forename: David B
authors.initials: DB
authors.lastname: Burr
authors.forename: Jiliang
authors.initials: J
authors.lastname: Li
authors.forename: Dana
authors.initials: D
authors.lastname: Michalská
authors.forename: Adrien
authors.initials: A
authors.lastname: Sipos
authors.forename: Helmut
authors.initials: H
authors.lastname: Petto
authors.forename: Astrid
authors.initials: A
authors.lastname: Fahrleitner-Pammer
authors.forename: Imre
authors.initials: I
authors.lastname: Pavo
mesh_terms: D019386:Alendronate / Q000627:therapeutic use*; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000627:therapeutic use*; D001842:Bone and Bones / Q000187:drug effects* / Q000473:pathology; D005260:Female; D006801:Humans; D008875:Middle Aged; D010024:Osteoporosis / Q000188:drug therapy*; D011446:Prospective Studies; D019379:Teriparatide / Q000494:pharmacology*
chemical_list: D050071:Bone Density Conservation Agents; D019379:Teriparatide; D019386:Alendronate