Bone Abstracts

Bones’ fracture resistance is achieved in vivo by adaptation to habitual loading. Aged bone can adapt to exercise1 but in female rodents ageing impairs the adaptive response to artificial loading2,3. This inconsistency led us to investigate whether treadmill exercise, sufficiently mild to not itself stimulate new bone formation, could rescue aged bone’s diminished response to artificial loading.Young adult 17-week...

Sclerostin, a product of osteocytes, is known to inhibit Wnt signaling by binding the LRP5/6 receptor.We investigated the effects of a mutated mouse sclerostin protein (muScl, R118A/R144A) with potential sclerostin antagonistic activity. In vitro, muScl fully competed with wild type sclerostin for binding to LRP6, whereas its IC50 for Wnt3a activity was 4× higher than sclerostin (i.e. 600 nM). Moreover, serum osteocalcin increased in mice a...

Skeletal development is characterized by sex-, race- and maturation-specific increases in bone strength. Studies using conventional QCT in the spine and femur, and peripheral QCT (pQCT) in the extremities provided insight into differences in compartment volumetric BMD (vBMD) and cortical dimensions but were limited by inadequate resolution to assess microarchitecture. For example, pQCT studies demonstrated that cortical vBMD was greater in females, while cortical section modul...

Background: Bone fragility and vascular calcifications are to the two main morbidities of the mineral and bone disorders associated with chronic kidney disease (CKD), resulting from a combination of abnormalities such as impaired GH axis, vitamin D deficiency, hyperparathyroidism, increased FGF23 levels, hypogonadism, denutrition and drug toxicity.Methods: In a single-centre ancillary study of the longitudinal prospective European 4C study (Cardiovascula...

Primary hyperparathyroidism is extremely rare in childhood and adolescence. Here we report a clinical case of a 15-year-3-month-old boy who began 2 years before with pain in his knees, genu varum, and fatigue. Physical examination showed severe genu valgum with an inter-malleolar distance of more than 30 cm. Biochemical tests showed hypercalcemia (12.2 mg/dl), hypophosphatemia (2.3 mg/ dl), hypercalciuria (6.4 mg/kg per day), high alkaline phosphatase (2812 IU/l), low 25-hydro...

Gene deletion or treatments with a cathepsin K (CatK) inhibitor in mature preclinical models result not only result in lower bone resorption but also in higher bone formation (BF) on both remodeling and modeling surfaces. Although increased production of clastokines and matrix-derived growth factors may explain the increased BF at remodeling surfaces, the mechanisms for greater BF at modeling surfaces, including the periosteum, remain unexplained. We hypothesized that the abse...

Antiresorptives consistently improve bone mass and structural strength in normally- and under-loaded bones, but concerns have been raised regarding potential effects on skeletal adaptation to fatigue loading, including damage accumulation and atypical fractures. We thus inhibited or activated osteoclasts with OPG-Fc or RANKL treatment, respectively, and evaluated bone damage and strength after fatigue in the early and later phases of repair. Adult male mice were treated with R...

This study was undertaken to evaluate the effect of whole-body vibration (WBV) with extremely low-amplitude on early-stage bone healing. Experiments were conducted with an approval of the Animal Research Committee of Osaka University Graduate School of Engineering Science. Male BALB/cByJJcl mice were subjected to a 0.5 mm drill-hole surgery on a tibial diaphysis at 14 weeks of age and divided into three groups (n=8 each) from the day after the surgery, which received ...

There is a growing evidence of the association between HIV infection and fracture risk. Independently of its cause (antiretroviral therapy (ART) or HIV), what remains most important is a prompt diagnosis. Although densitometry is the gold standard, sometimes this technique is not as accurate as necessary in clinical practice. A new validated tool for early and more accurate diagnosis is presented.MethodsIn a HIV group of patients, ...

Fibroblast growth factor-23 (FGF23) is a bone derived phosphate-regulating hormone which is elevated in hypophosphataemic rickets. Recent findings demonstrate iron deficiency as a potential mediator of FGF23 expression and murine studies have shown in utero effects of maternal iron deficiency leading to increased FGF23 concentration and disordered bone development (Clinkenbeard. JBMR 2013). Children with rickets in rural Gambia, West Africa, have high prevalences of i...