Bone Abstracts

Background: Pseudohypoparathyroidism (PHP) is a group of heterogeneous endocrine disorders characterised by hormone resistance, primarily to parathyroid hormone (PTH). The resistance is caused by defects in the GNAS gene, which encodes the Gsα protein that activates the cAMP pathway. PHP patients demonstrate elevated plasma PTH, hypocalcaemia, hyperphosphataemia with normal renal function. PTH resistance can be confirmed by Ellsworth-Howard test (PTH s...

Fibroblast growth factor-23 (FGF23) is a major regulator of phosphate metabolism often elevated in genetic hypophosphataemic disorders and in chronic kidney disease–bone mineral disorder (CKD–BMD). Recent studies have identified relationships between FGF23 and vitamin D.Objectives: To determine the relationship between vitamin D and FGF23 metabolism in CKD.Method: We used randomized samples from patient...

Kit ligand/c-Kit receptor tyrosine kinase complex has been implicated as a target for bone remodeling process. Loss of function mutation in c-Kit causes low bone mass in KitW/W-v (W/Wv) mice. However, these mice are sterile and it is unclear whether the observed skeletal phenotype is secondary to sex hormone deficiency. To address this question, the skeletal phenotype of KitW...

Background: Vitamin D plays an important role in calcium and phosphate homeostasis. Circulating 25 hydroxyvitamin D [25(OH)D] is metabolised into its biologically active form 1,25-dihydroxyvitamin D [1,25-d(OH)D] by the actions of 1α hydroxylase, and into inactive 2metabolite 24,25-dihydroxyvitamin D [24,25-d(OH)D] by 24-hydroxylase. Recent studies suggest the production of 1,25-d(OH)D) from 25(OH)D is 24,25-d(OH)D dependent. Genetic mutations of CYP24A1 gene resulting in...

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...

Introduction: The vitamins as B6, C, or D are involved in serotonin metabolism but mostly in central neurotransmitter pathways. There are very few clear data related to 25-OH vitamin D status and serum serotonin (SS) levels.Aim: We analyze the SS and 25-OH D.Materials and methods: We included women in menopause. The serum serotonin (SS; normal 100–400 ng/ml) and 25-OH vitamin D (normal 30–100 ng/ml) were performed in fast...

Objectives: Adolescent idiopathic scoliosis (AIS) is a complex three-dimensional spinal deformity associated with low bone mass. Our previous clinical trial demonstrated the anabolic bone effect of vibration treatment (VT) at the femoral neck in AIS subjects. The therapeutic effect was more pronounced in those with optimal serum 25(OH) Vit-D level (>40 nmol/l). To investigate possible factor interaction between Vit-D and VT on their anabolic bone effects, this in-vitro...

Introduction: Effective screening for vitamin D (Vit-D) insufficiency is desirable. Pigmentation of unexposed (constitutive) skin and exposed (facultative) skin can be measured with skin colourimetry to assess dermal capability in synthesizing Vit-D and degree of sunlight exposure respectively. This study aimed at evaluating whether skin colourimetry could be used to screen Vit-D insufficiency among adolescents.Methods: 240 healthy adolescents (mean age=...

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...

see P21....