Bone Abstracts

Osteoclasts secrete acid and cathepsin K to dissolve the mineral and digest the organic matrix of bone, cartilage and dentine. The secretions are by necessity destructive and potentially harmful to the cell itself and are therefore trafficked through the cell in membrane bound vesicles. Secretion takes place over a specialised membrane compartment, the ruffled border, which is only present in resorbing osteoclasts. The ruffled border membrane and the vesicles in its vicinity h...

Background: Low vitamin D concentrations among children and adolescents at northern latitudes are frequently observed. Also, inverse associations between 25-hydroxyvitamin D (25(OH)D) and PTH concentrations have been found in children of different ages. More studies on the link between vitamin D status and childhood bone health are needed.Objective: To evaluate the status of serum 25(OH)D in autumn and the association between 25(OH)D concentrations and b...

Objectives: Young male jockeys undertake calorie restriction and high volumes of physical activity during periods of musculoskeletal growth and development. Previous research shows that jockeys have compromised bone health1–4 and display disordered eating5–7. Restricted intakes of calcium and vitamin D, together with excessive amounts of exercise, increase the risk of osteoporosis in males8. The aim of this study was to establish whet...

Background: In the National Osteoporosis Guide 2014 all the patients are first recommended adequate calcium and vitamin D intake. For additional treatment US FDA approves the use of medications within seven different drug groups, but no magnesium. We have therefore studied the beneficial effect of Mg added to a Ca/vitamin D regime.Study: Fifty healthy women aged above 70 years recruited from elderly center were randomized into a Mg supplementation group ...

Muscle mass and strength are known to enhance pediatric gains in bone mineral and bone cross-sectional area, providing a rationale for targeting muscle early in life as a means of improving bone health. We have recently found that the cytokine-like hormone leptin, a well-established adipokine, is abundant in skeletal muscle. Leptin levels normalized for total protein are actually higher in mouse skeletal muscle than in mouse adipose tissue, and studies in human subjects have d...

Biographical DetailsDr HamrickDr Hamrick is Regent’s Professor in the Department of Cellular Biology & Anatomy at the Medical College of Georgia, Augusta University (formerly Georgia Health Sciences University), Augusta, Georgia, USA. He received his PhD in Cellular & Integrative Biology from Northwestern University and completed postdo...

Background: Paget’s disease of Bone (PDB) has a strong genetic component and a candidate locus for the disease has been identified on chromosome 14q32, tagged by rs10498635 located within RIN3 (Albagha et al, Nat Genet 2011). RIN3 encodes a protein that acts as a guanine nucleotide exchange factor for Rab5b and Rab31. Here we investigated the candidacy of RIN3 as a predisposing gene for PDB.Methods: We studied expression of RIN3 by quantita...

Background: Vitamin D deficiency is highly prevalent and can be associated with adverse health outcomes. Few studies have evaluated the effects of daily consumption of milk fortified with a high dose of vitamin D in a large cohort of healthy postmenopausal women.Objectives: To determine the effect of daily intake of milk enriched with vitamin D (with or without fructooligosaccharides (FOS)) on vitamin D status, bone mass and cardiovascular risk factors.<...

Objective: To study association of VDR gene Fok1 polymorphism locus on bone mass accrual in adolescent girls.Methods: An intervention trial was carried out in 102 girls aged 8–16 years (Pune, India). All girls received 500 mg elemental calcium (daily) and 30 000 IU of vitamin D3 quarterly for 1 year. Outcome variables were measured at baseline and end of the year. Serum levels of ionised calcium (iCa), inorganic phosphorous, parathyroid hor...

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<...