Bone Abstracts

Spatial distributions of major and minor chemical elements are supposed to change during tissue maturation and due to bone diseases. Previous studies suggested that osteocytes have the ability to interact with the bone matrix of their environment. For this interaction osteocytes make use of the big inner surface of the osteocyte lacuno-canalicular network (OLCN) in which they are accommodated. The aim of this study was to quantify spatial correlations between the elemental com...

We retrospectively analyzed the incidence of hip re-fractures in Austrian hip fracture patients devoid of anti-osteoporotic drug treatment, taking vs not taking proton pump inhibitors (PPIs).For 31,668 patients ≥50 years sustaining a hip fracture in Austria between July 2008 and December 2010, information on hip re-fractures with follow-up until June 2011 and on filed prescriptions of PPIs and anti-osteoporotic drugs between July 2007 and June 2011...

Deficiency of Cyclophilin B (CyPB) causes recessively inherited Type IX osteogenesis imperfecta, a moderately severe to lethal bone dysplasia. CyPB, encoded by PPIB, is an ER-resident peptidyl-prolyl cis-trans isomerase (PPIase) that catalyzes the rate-limiting step in collagen folding, and also functions as a component of the collagen prolyl 3-hydroxylation complex. We previously demonstrated in a Ppib−/− mouse model that CyPB PPIase activity r...

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: FGF23 is expressed in clusters of osteocytes at the trabecular periphery suggesting that FGF23-expressing osteocytes are confined to specific basic multicellular units (BMUs) at the trabecular surface. Higher numbers of FGF23-expressing osteocytes are found in chronic kidney disease (CKD) patients with preserved skeletal mineralization indices. We thus combined immunohistochemistry and quantitative backscattered electron imaging (qBEI) to explore the hypothesis tha...

Objectives: Mice with a non-functioning vitamin D receptor (VDR mutants) develop severe secondary hyperparathyroidism, which can be rescued by a diet enriched with calcium, phosphate and lactose. In this work, we studied the effects of a low calcium challenge (CD), normal calcium (ND) and a calcium enriched rescue diet (RD) on the bone mineralization density distribution (BMDD) and osteocyte lacunae sections (OLS) in these mice.Methods: BMDD and OLS were...

Background and methods: A specific skeletal complication in children with CKD is growth impairment. The effects of recombinant human growth hormone (rhGH) therapy on bone turnover and bone material quality are not well understood. Bone matrix mineralization density distribution (BMDD) as assessed by quantitative backscattered electron microscopy (qBEI) is an important determinant of bone material quality and reflects bone turnover (average tissue age) and mineralization kineti...

Classical osteogenesis imperfecta (OI) is caused by mutations in the two genes encoding type I collagen. OI is associated with low bone mass and abnormally high bone matrix mineralization. The Brtl/+ OI mouse is a knock-in model caused by a glycine substitution in one COL1A1 allele. Brtl/+ pups display 30% perinatal lethality; survivors have small size and brittle bone. Unexpectedly, homozygous Brtl/Brtl pups, producing only mutant collagen, have normal survival rates...

The development of optimally performing biomaterials mimicking the natural physiological processes underlying bone repair is essential for non-healing large bone lesions. We sought to develop scaffolds that fill the lesions and improve bone healing. We tested three scaffolds comprised of varying percentages of lactide (LA), caprolactone (CL), and methacrylate produced by two-photon photopolymerization; LCM 3 (8:2; 85%), 4 (9:1; 90%), and 6 (9:1; 40%). We hypothesized that the ...

Bone mineral density (BMD) as measured by quantitative computed tomography (QCT) is biased by the variable marrow composition since marrow fat reduces the apparent BMD. We developed a marrow densitometry (MD) method that identifies subvolumes in the vertebrae that consist of bone marrow only (bone voids) and determines their average mineral equivalent density values. The method was developed for use with in vivo high resolution QCT (HR-QCT). HR-QCT still has limited s...