title: Sheep model for osteoporosis: sustainability and biomechanical relevance of low turnover osteoporosis induced by hypothalamic-pituitary disconnection.
abstract: Hypothalamo-pituitary disconnection (HPD) leads to low bone turnover and osteoporosis in sheep. To determine the sustainability of bone loss and its biomechanical relevance, we studied HPD-sheep 24 months after surgery (HPD + OVX-24) in comparison to untreated control (Control), ovariectomized sheep (OVX), and sheep 12 months after HPD (HPD + OVX-12). We performed histomorphometric, HR-pQCT, and qBEI analyses, as well as biomechanical testing of all ewes studied. Twenty-four months after HPD, histomorphometric analyses of the iliac crest showed a significant reduction of BV/TV by 60% in comparison to Control. Cortical thickness of the femora measured by HR-pQCT did not change between 12 and 24 months after HPD but remained decreased by 30%. These structural changes were caused by a persisting depression of osteoblast and osteoclast cellular activity. Biomechanical testing of the femora showed a significant reduction of bending strength, whereas calcium content and distribution was found to be unchanged. In conclusion, HPD surgery leads to a persisting low turnover status with negative turnover balance in sheep followed by dramatic cortical and trabecular bone loss with consequent biomechanical impairment.
authors: Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Martinistr. 52, Hamburg, 20246, Germany.
authors: Ralf
authors: R
authors: Oheim
authors: Frank Timo
authors: FT
authors: Beil
authors: Till
authors: T
authors: Köhne
authors: Tim
authors: T
authors: Wehner
authors: Florian
authors: F
authors: Barvencik
authors: Anita
authors: A
authors: Ignatius
authors: Michael
authors: M
authors: Amling
authors: Iain J
authors: IJ
authors: Clarke
authors: Pia
authors: P
authors: Pogoda
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000502:physiology; D001862:Bone Resorption / Q000503:physiopathology; D001842:Bone and Bones / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D007031:Hypothalamus / Q000502:physiology* / Q000601:surgery*; D010006:Osteoblasts / Q000378:metabolism / Q000473:pathology; D010010:Osteoclasts / Q000378:metabolism / Q000473:pathology; D010012:Osteogenesis / Q000502:physiology; D010024:Osteoporosis / Q000378:metabolism*; D010052:Ovariectomy; D010902:Pituitary Gland / Q000502:physiology* / Q000601:surgery*; D012756:Sheep