Bone Abstracts

Background: Despite the large amount of studies published on the association of vitamin D deficiency with higher incidence of falls and fractures, the threshold for a sufficient serum 25(OH)D concentration remains subject to a considerable debate. There has also been no clear consensus on the assessment and treatment of vitamin D deficiency.Objective: To examine the prevalence of vitamin D deficiency and/or insufficiency and its impact on calcium/phospha...

Background: Despite the large amount of studies published on the association of vitamin D deficiency with higher incidence of falls and fractures, the threshold for a sufficient serum 25(OH)D concentration remains subject to a considerable debate. There has also been no clear consensus on the assessment and treatment of vitamin D deficiency.Objective: To examine the prevalence of vitamin D deficiency and/or insufficiency and its impact on calcium/phospha...

Fibroblast growth factor-23 (FGF23) is a hormone originating from osteocytes with suppressive actions on renal phosphate reabsorption and vitamin D synthesis. We recently identified FGF23 as a calcium-conserving hormone, regulating the membrane transport of the epithelial calcium channel TRPV5 in distal renal tubules. Here, we analyzed the long term sequelae of Fgf23 deficiency and renal calcium wasting on bone and mineral metabolism in 9-month-old mice lacking both Fgf23<...

Lack of Klotho, the co-receptor for the bone-derived hormone fibroblast growth factor-23 (FGF23), leads to a severe impairment in bone mineralization in mice. However, the mechanisms underlying the Klotho deficiency-associated defects in bone mineralization are still poorly understood. Here, we sought to elucidate the vitamin D independent role of Klotho in bone mineralization. To ablate increased vitamin D signaling in Klotho knockout mice (Kl−/−), we c...

Background: Magnetic resonance imaging (MRI) is used clinically to assess bone marrow, muscle and joints. The assessment of cortical and trabecular structure using MRI may provide further insight into the muscle–bone–bone marrow unit. Previous studies using MRI to evaluate microarchitecture are confined to research due to the need for specially adapted coils and navigator software to limit motion artifact. We present a novel statistical method using HRpQCT to determi...