Bone Abstracts

Objectives: Single nucleotide polymorphisms (SNP) in genes related to vitamin D metabolism have been associated with 25-hydroxyvitamin D (25(OH)D) status, but these relationships have not been examined in pregnancy or following antenatal vitamin D supplementation. We assessed whether SNPs in DHCR7 (7-dehydrocholesterol reductase), CYP2R1 (25-hydroxylase), CYP24A1 (24-hydroxylase) and GC (Vitamin D binding protein) were associated with the re...

Trabecular bone score (TBS) extracts a texture parameter from pixel grey-level variations in DXA lumbar spine images. The TBS is claimed to be a measure of trabecular structure and was validated in an in-vitro study of vertebral bodies with micro-CT1. TBS has shown the potential for fracture pre-diction in adults2. However, data are sparse regarding the reliability and usefulness of TBS3 and the method has not previously been applied i...

Osteocalcin, the neurotrophins BDNF/NGF and Oxytocin(Oxt) have pleiotropic effects on energy metabolism, bone mass, reproduction and brain functions suggesting a coordinated regulation. The carboxylated osteocalcin(Ost) acts on bone, while the uncarboxylated Ost shows hormone-like actions. NGF regulates female fertility elevating LH, Ost−/− mice show high LH in spite of decreased testosterone. BDNF/NGF-Oxt-Ost interactions was investigated by RT-PCR meas...

Bone is a complex tissue constituted by a mineral phase, hydroxyapatite, and an organic phase, mainly represented by collagen type I. Specialized cells are responsible for bone formation and remodeling. Osteoblasts represent the bone forming cells, osteocyte are the orchestrator of bone remodeling through regulation of the other bone cells activity, by functioning as endocrine cells and by acting as mechanosensor, and osteoclasts, the bone resorbing cells. Mesenchymal osteopro...

Objectives: Osteogenesis Imperfecta (OI) type XIV is a recessive OI form characterized by bone fragility, multiple fractures and growth retardation. It is caused by mutation in TMEM38B gene encoding the endoplasmic reticulum (ER) channel TRIC-B. This channel allows the transport of K+ across the ER membrane modulating Ca2+ flux. Defective ER Ca2+ impaires collagen type I synthesis, likely affecting the activity of ER enzymes involved in its post translational modification. To ...

Objectives: Different versions of the Childhood Health Questionnaire (CHAQ) have been used in Paediatric Rheumatology since 1994 to establish levels of functional disability. To date, use of the CHAQ has not been reported in Osteogenesis Imperfecta (OI). The aim of this study was to establish if disability scores generated from a modified CHAQ (MCHAQ) correlate with OI severity.Methods: The MCHAQ was developed to reflect the specific needs of children wi...

Objectives: Osteogenesis imperfecta (OI) is a heritable disorder characterized by bone deformity and skeletal fragility. Cartilage associated protein (CRTAP), proline 3-Hydroxylase 1 (P3H1) and Cyclophylin B (PPIB) are components of the endoplasmic reticulum (ER)-resident complex involved in the 3-hydroxylation of specific proline residues in collagen type I α chains. Mutations in these proteins are responsible for recessive OI type VII, VIII and IX, respectively. Murine ...

Several environmental and genetic factors may interfere on bone mass in children. However, the pediatric studies that approach the socioeconomic status and quantitative ultrasound (QUS) parameters are scarce. The aim of this study was to compare the bone mass in girls from 7 to 15 years old of different socioeconomic status. The sample consisted of 860 Brazilian girls (8.95±1.32) of different socioeconomic status. The bone mass parameter, amplitude dependent speed sound (...

Objectives: The Brtl mouse, a unique model for the autosomal dominant forms of osteogenesis imperfecta was used to prove the feasibility of a lentiviral-shRNA-based strategy to improve collagen quality by targeting the mutant Col1a1 allele at the point mutation responsible for the causative substitution Gly349Cys. The ability to specifically suppress the mutant allele should convert the moderate Brtl outcome to the mild one caused by quantitative defect.<p class="...

Background: Proline and hydroxyproline account for ~25% of aminoacids in collagen., Prolidase (peptidase D (EC 3.4.14.9)), cleaves iminodipeptides with a C-terminal proline or hydroxyproline, playing a major role in collagen catabolism. Mice with prolidase deficiency (PD) present with varied phenotypes including reduced size compared to wild-type littermates. We measured structural and mechanical properties of bones in PD mice.Methods: Whole femurs from ...