Context: Evidence suggests that both bone mineral density and bone quality should be taken into account when assessing bone strength and fracture risk. Bone quality is a multi-factor entity, of which bone architecture and material properties are two important components. Matrix mineralization, hydroxyapatite characteristics and collagen cross-link ratio are key determinants of material properties. Fourier Transform Infrared Imaging (FTIRI) yields data on these characteristics from bone sections.

Objective: We sought to determine collagen cross-link ratios and matrix mineralization of bone from patients randomized to teriparatide [rhPTH (1-34)] treatment using FTIRI.

Design: The Fracture Prevention Trial was randomized, double-blind and placebo-controlled

Setting: Global clinical research centers

Patients: Postmenopausal women with osteoporosis

Interventions: Patients were randomized to receive daily sc injections of either placebo (n = 12), 20 µg (n = 13) or 40 µg (n = 13) of teriparatide. Biopsies were obtained after either 12 months of treatment or at the end of treatment (range 19-24 months for end of treatment paired biopsies).

Main Outcome Measures: Biopsies were analyzed by FTIRI to determine the matrix mineralization (mineral:matrix), mineral crystallinity and collagen cross-link ratio (pyridinoline/dehydro-dihydroxy-lysinonorleucine) with a spatial resolution of 6.3 µm.

Results: Patients administered teriparatide 20 and 40 µg/day exhibited significantly lower matrix mineralization, mineral crystallinity and collagen cross-link ratio when compared with placebo.

Conclusions: These findings indicate that the bone-forming effect of teriparatide results in bone with a molecular profile reminiscent of younger bone.