Bone Abstracts

Objectives: Osteocytes play a major role in bone metabolism as mechanosensors, key regulators of osteoblast and osteoclast activity and of the mineral homeostasis. Therefore the assessment of osteocytes characteristics is important to understand bone pathology. We propose to study indirectly the osteocytes by performing quantitative backscattered electron imaging to quantify the sectioned osteocyte lacunae density and size in 2D on bone samples.Methods: ...

Objectives: Intravenous cyclical bisphosphonates are widely used to treat children with moderate to severe osteogenesis imperfecta (OI). They increase bone mineral density (BMD), diminish fracture rates and improve mobility. Bisphosphonates are often discontinued when growth is completed. We aimed to determine if the skeletal gains achieved with bisphosphonates persist after their discontinuation in patients with OI.Methods: We assessed patients with OI ...

Osteogenesis imperfecta (OI) type V is caused by a unique dominant mutation (c.−14C>T) in IFITM5, which encodes BRIL, a transmembrane ifitm-like protein most strongly expressed in osteoblasts, while type VI OI is caused by recessive null mutations in SERPINF1, encoding pigment epithelium-derived factor (PEDF). We identified a 25-year-old woman with severe OI, whose dermal fibroblasts and cultured osteoblasts displayed minimal secretion of PEDF, but ...

Background and methods: Pigment epithelium-derived factor (PEDF) is a potent antiangiogenic factor, ubiquitously expressed and secreted in human tissues. Hypertrophic cartilage and osteoblasts express PEDF that binds to type I collagen and glycosaminoglycans in the extracellular matrix. Two rare forms of osteogenesis imperfecta (OI) with intact collagen synthesis are associated with PEDF deficiency. Histological observations revealed excessive osteoid formation and prolonged m...

Objective: We compared the efficacy and safety of burosumab, a monoclonal antibody against FGF23, to conventional therapy [oral phosphate and active vitamin D (Pi/D)] in children with X-linked hypophosphatemia (XLH).Methods: In this Phase 3 trial (NCT02915705), 61 children with XLH (1-12 years-old) were randomized 1:1 after a 7-day Pi/D washout to receive burosumab starting at 0.8 mg/kg SC Q2W or reinitiate Pi/D optimally titrated by investigators. Eligi...