Bone Abstracts

There is wide variation in the dose-response to oral vitamin D and the increment in plasma 25(OH)D decreases per unit vitamin D given. We hypothesised that this is related to increased 25(OH)D catabolism as reflected in 25OHD half-life (25(OH)D3 t1/2).Design: 25(OH)D3 t1/2 was measured with a stable isotope (SI) technique in older (70y+) men and women in the UK during winter before (<...

see P221b....

Background, subjects and methods: Vitamin D insufficiency in older people in the UK is common and may cause secondary hyperparathyroidism and bone loss. In a randomised, double blind intervention trial to optimise “Vitamin D status in Older People’ (VDOP) three oral dosages of vitamin D3 (12 kIU, 24 kIU or 48 kIU/month) were given for 12 months to 375 participants aged over 70 years (ANOVA) adjustment for covariables with results below presented in ascendi...

Low circulating levels of total 25-hydroxyvitamin D (25OHD) have been reported in obese people of different ethnicities in several countries. Low total 25OHD in obesity could be due to lower binding proteins (with normal free 25OHD), lower dietary intake or sunlight exposure, greater volume of distribution (pool size) or more rapid metabolic clearance.The aims of this study were to determine if free 25OHD and 1,25-dihydroxyvitamin D (1,25(OH)2...

Maternal vitamin D status has been positively associated with infant bone mass in observational studies. We therefore evaluated whether 1000 IU/day cholecalciferol during pregnancy would lead to greater offspring bone mass at birth, in a UK, multicentre, randomised, double-blind, placebo-controlled trial (MAVIDOS, ISRCTN82927713).At 12 weeks’ gestation, pregnant women with a serum 25-hydroxyvitamin D [25(OH)D] 25-100 nmol/l were randomised to either...

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...

Background: Osteoclasts are unique multinucleated cells that originate from the fusion of monocytes. They are the only cells known to be capable of bone resorption. Interestingly, the foreign body multinucleated giant cell (FBGC) arises from the same lineage as the osteoclast, and they share numerous similar characteristics, among which the expression of tartrate resistant acid phosphatase (TRAcP). Yet, it is not known whether the FBGC has the capacity to resorb bone.<p cl...

Background: Osteoclasts (OCs) are bone-degrading cells that differentiate from the monocyte/macrophage lineage. In human, three monocyte subsets have been identified: classical, intermediate and non-classical monocytes. We have previously demonstrated that comparable numbers of OCs can be generated from these subsets on plastic, but that the number of OCs significantly differs when the monocytes are cultured on bone. It is plausible that the observed differences are associated...

Background: Fibrodysplasia Ossificans Progressiva (FOP) is a progressive disease characterized by periods of heterotopic ossification, often in ligaments. The underlying mechanism is far from clear, partially due to limited access to patient-derived cell models. Periodontal ligament fibroblasts (PLF) from extracted teeth can potentially be used to study deviant bone remodelling processes in vitro since these cells are derived from actual ligaments. They further provid...