Bone Abstracts

Activins belong to the transforming growth factor-β superfamily, and they regulate bone formation by controlling both osteoclast and osteoblast behaviour. We have previously shown that activin-A strongly inhibited matrix mineralization in osteoblast cultures, and that activin A-signalling was most effective before the onset of mineralization.The aim of this study was therefore to investigate how an early activin-A pulse affected osteoblast mineraliz...

Vitamin D deficiency is common in older persons and non-western immigrants. Vitamin D is often started in loading doses of 50 000 IU/ml solution. Though, generally considered safe, this highly concentrated solution carries some risks as is illustrated by the following cases. A woman of >80 years old was admitted with hypercalcemia, calcium 3.27 mmol/l. She complained of nausea, thirst and polyuria for 3 months. History included cholecystitis, atrial fibrillation, myocardia...

The murine osteoprogenitor cell line, KS483 (Percuros, The Netherlands) is a well-established model for investigation of osteoblast differentiation and bone formation processes. The mesenchymal characteristics of this cell line allow it to differentiate into either adipocytes or mature, mineralizing osteoblasts. Various phases can be distinguished during osteoblast differentiation and maturation; namely proliferation, matrix formation, matrix maturation, and mineralization.</p...

Although trials have shown that exercise has positive effects on bone mineral density (BMD), not all exercise modalities are osteogenic and the majority of exercise trials have been conducted in older women. The aim of this study was to systematically review trials examining the effect of weight-bearing and resistance-based exercise modalities on the BMD of hip and lumbar spine of middle-aged and older men. Eight electronic databases were searched in August 2012. Only randomis...

Young transsexuals at a minimum age of 12 years are treated with GnRH-analogues (GnRHa) to suspend pubertal development until the addition of hormones of the desired sex is started at a minimum age of 16 years. The effect of this treatment on adult bone mineral density (BMD) is still unknown. We aimed to assess BMD at the age of 22, as this is near its peak in healthy individuals.In this prospective observational study 19 female to male (FtM) and 16 male...

Background: Long-term use of bisphosphonates has raised concerns about the association with Atypical Femur Fractures (AFFs) that have been reported mainly in postmenopausal women.Clinical case: An 18-year-old patient with juvenile osteoporosis based on X-linked osteoporosis due to a PLS3 mutation developed a low trauma femoral fracture after seven years of intravenous and two years of oral bisphosphonate use, fulfilling the revised ASBMR diagnostic crite...

Objectives: Strong coordination between osteoblasts and bone marrow cells is fundamental for the regulation of healthy bone turnover and other (patho)physiological processes. Extracellular vesicles (EVs) mediate communication between cells via horizontal transfer of proteins and nucleic acids. Osteoblasts secrete EVs in the form of matrix vesicles involved in bone mineralization, however, information about a role in intercellular communication is still lacking. In this study, ...

Since the identification of LRP5 as the causative gene for the osteoporosis pseudoglioma syndrome (OPPG) as well as the high bone mass (HBM) phenotype, LRP5 and the Wnt/β-catenin signalling have been extensively studied for their role in the differentiation and proliferation of osteoblasts, in the apoptosis of osteoblasts and osteocytes and in the response of bone to mechanical loading. However, more recently the direct effect of LRP5 on osteoblasts and bone formation has...

Introduction: Vitamin D deficiency has been associated with impaired physical functioning and several chronic diseases and might thereby affect quality of life and self-rated health. The aim of this study was to assess relationships of serum 25-hydroxyvitamin D (25(OH)D) with quality of life and self-rated health, and to examine whether physical performance and number of chronic diseases mediate these relationships.Methods: Data were obtained from the LA...

Introduction: We describe a monozygotic twin pair, of which one boy was diagnosed with anorchia. Both were followed-up till age 17.Case report: At birth, in one twin 46 XY boy (A), testes were not palpable while his brother (B) was unaffected. Stimulation with human chorionic gonadotrophin (hCG) and orchidopexia were unsuccessful at age 3. A second hCG-stimulation test was performed at age 8, where serum testosterone response failed to increase. No testi...