Pancreas deficiency modifies bone development in the ovine fetus near term.

Hormones have an important role in the regulation of fetal growth and development, especially in response to nutrient availability in utero. Using micro-CT and an electromagnetic three-point bend test, this study examined the effect of pancreas removal at 0.8 fraction of gestation on the developing bone structure and mechanical strength in fetal sheep. When fetuses were studied at 10 and 25 days after surgery, pancreatectomy caused hypoinsulinaemia, hyperglycaemia and growth retardation which was associated with low plasma concentrations of leptin and a marker of osteoclast activity and collagen degradation. In pancreatectomized fetuses compared to control fetuses, limb lengths were shorter, and trabecular (Tb) bone in the metatarsi showed greater bone volume fraction, Tb thickness, degree of anisotropy and porosity, and lower fractional bone surface area and Tb spacing. Mechanical strength testing showed that pancreas deficiency was associated with increased stiffness and a greater maximal weight load at fracture in a subset of fetuses studied near term. Overall, pancreas deficiency in utero slowed the growth of the fetal skeleton and adapted the developing bone to generate a more compact and connected structure. Maintenance of bone strength in growth-retarded limbs is especially important in a precocial species in preparation for skeletal loading and locomotion at birth

Dietary Protein and Bone Health Across the Life-Course : an updated systematic review and meta-analysis over 40 years

Abstract Purpose: This systematic review and meta-analysis analysed the relationship between dietary protein and bone health across the life-course. Methods: The PubMed database was searched for all relevant human studies from the 1st 4 January 1976 to 22nd January 2016, including all bone outcomes except calcium metabolism. Results: The searches identified 127 papers for inclusion, including 74 correlational studies, 23 fracture or osteoporosis risk studies and 30 supplementation trials. Protein intake accounted for 0 - 4% of areal BMC and areal BMD variance in adults and 0-14% of areal BMC variance in children and adolescents. However, when confounder adjusted (5 studies) adult lumbar spine and femoral neck BMD associations were not statistically significant. There was no association between protein intake and relative risk (RR) of osteoporotic fractures for total (RR(random) = 0.94; 0.72 to 1.23, I2=32%), animal (RR (random) = 0.98; 0.76 to 1.27, I2 = 46%) or vegetable protein (RR (fixed)= 0.97 (0.89 to 1.09, I2 = 15%). In total protein supplementation studies, pooled effect sizes were not statistically significant for LSBMD (total n=255, MD(fixed)=0.04 g/cm2 (0.00 to 0.08, P=0.07), I2=0%) or FNBMD (total n=435, MD(random)=0.01 g/cm2 (-0.03 to 0.05, P=0.59), I2=68%). Conclusions: There appears to be little benefit of increasing protein intake for bone health in healthy adults but there is also clearly no indication of any detrimental effect, at least within the protein intakes of the populations studied (around 0.8-1.3 g/Kg/day). More studies are urgently required on the association between protein intake and bone health in children and adolescents. Key Words: Aging, Epidemiology, IGF-1, Nutrition, Osteoporosis, Die

In vivo delivery of VEGF RNA and protein to increase osteogenesis and intraosseous angiogenesis

Deficient bone vasculature is a key component in pathological conditions ranging from developmental skeletal abnormalities to impaired bone repair. Vascularisation is dependent upon vascular endothelial growth factor (VEGF), which drives both angiogenesis and osteogenesis. The aim of this study was to examine the efcacy of blood vessel and bone formation following transfection with VEGF RNA or delivery of recombinant human VEGF165 protein (rhVEGF165) across in vitro and in vivo model systems. To quantify blood vessels within bone, an innovative approach was developed using high-resolution X-ray computed tomography (XCT) to generate quantifable three-dimensional reconstructions. Application of rhVEGF165 enhanced osteogenesis, as evidenced by increased human osteoblast-like MG-63 cell proliferation in vitro and calvarial bone thickness following in vivo administration. In contrast, transfection with VEGF RNA triggered angiogenic efects by promoting VEGF protein secretion from MG-63VEGF165 cells in vitro, which resulted in signifcantly increased angiogenesis in the chorioallantoic (CAM) assay in ovo. Furthermore, direct transfection of bone with VEGF RNA in vivo increased intraosseous vascular branching. This study demonstrates the importance of continuous supply as opposed to a single high dose of VEGF on angiogenesis and osteogenesis and, illustrates the potential of XCT in delineating in 3D, blood vessel connectivity in bone

Study protocol for a randomized controlled trial comparing mindfulness-based cognitive therapy with maintenance anti-depressant treatment in the prevention of depressive relapse/recurrence: the PREVENT trial.

BACKGROUND: Depression is a common and distressing mental health problem that is responsible for significant individual disability and cost to society. Medication and psychological therapies are effective for treating depression and maintenance anti-depressants (m-ADM) can prevent relapse. However, individuals with depression often express a wish for psychological help that can help them recover from depression in the long-term. We need to develop psychological therapies that prevent depressive relapse/recurrence. A recently developed treatment, Mindfulness-based Cognitive Therapy (MBCT, see http://www.mbct.co.uk) shows potential as a brief group programme for people with recurring depression. In two studies it has been shown to halve the rates of depression recurring compared to usual care.This trial asks the policy research question, is MBCT superior to m-ADM in terms of: a primary outcome of preventing depressive relapse/recurrence over 24 months; and, secondary outcomes of (a) depression free days, (b) residual depressive symptoms, (c) antidepressant (ADM) usage, (d) psychiatric and medical co-morbidity, (e) quality of life, and (f) cost effectiveness? An explanatory research question asks is an increase in mindfulness skills the key mechanism of change? METHODS/DESIGN: The design is a single blind, parallel RCT examining MBCT vs. m-ADM with an embedded process study. To answer the main policy research question the proposed trial compares MBCT plus ADM-tapering with m-ADM for patients with recurrent depression. Four hundred and twenty patients with recurrent major depressive disorder in full or partial remission will be recruited through primary care. Depressive relapse/recurrence over two years is the primary outcome variable. The explanatory question will be addressed in two mutually informative ways: quantitative measurement of potential mediating variables pre/post-treatment and a qualitative study of service users' views and experiences. DISCUSSION: If the results of our exploratory trial are extended to this definitive trial, MBCT will be established as an alternative approach to maintenance anti-depressants for people with a history of recurrent depression. The process studies will provide evidence about the effective components which can be used to improve MBCT and inform theory as well as other therapeutic approaches. TRIAL REGISTRATION NUMBER: ISRCTN26666654.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

Genetically-programmed, mesenchymal stromal cell-laden & mechanically strong 3D bioprinted scaffolds for bone repair

Additive manufacturing processes used to create regenerative bone tissue engineered implants are not biocompatible, thereby restricting direct use with stem cells and usually require cell seeding post-fabrication. Combined delivery of stem cells with the controlled release of osteogenic factors, within a mechanically-strong biomaterial combined during manufacturing would replace injectable defect fillers (cements) and allow personalized implants to be rapidly prototyped by 3D bioprinting.Through the use of direct genetic programming via the sustained release of an exogenously delivered transcription factor RUNX2 (delivered as recombinant GET-RUNX2 protein) encapsulated in PLGA microparticles (MPs), we demonstrate that human mesenchymal stromal (stem) cells (hMSCs) can be directly fabricated into a thermo-sintered 3D bioprintable material and achieve effective osteogenic differentiation. Importantly we observed osteogenic programming of gene expression by released GET-RUNX2 (8.2-, 3.3- and 3.9-fold increases in OSX, RUNX2 and OPN expression, respectively) and calcification (von Kossa staining) in our scaffolds. The developed biodegradable PLGA/PEG paste formulation augments high-density bone development in a defect model (~2.4-fold increase in high density bone volume) and can be used to rapidly prototype clinically-sized hMSC-laden implants within minutes using mild, cytocompatible extrusion bioprinting.The ability to create mechanically strong 'cancellous bone-like’ printable implants for tissue repair that contain stem cells and controlled-release of programming factors is innovative, and will facilitate the development of novel localized delivery approaches to direct cellular behaviour for many regenerative medicine applications including those for personalized bone repair

The chorioallantoic membrane (CAM) assay for the study of human bone regeneration: a refinement animal model for tissue engineering.

Biomaterial development for tissue engineering applications is rapidly increasing but necessitates efficacy and safety testing prior to clinical application. Current in vitro and in vivo models hold a number of limitations, including expense, lack of correlation between animal models and human outcomes and the need to perform invasive procedures on animals; hence requiring new predictive screening methods. In the present study we tested the hypothesis that the chick embryo chorioallantoic membrane (CAM) can be used as a bioreactor to culture and study the regeneration of human living bone. We extracted bone cylinders from human femoral heads, simulated an injury using a drill-hole defect, and implanted the bone on CAM or in vitro control-culture. Micro-computed tomography (?CT) was used to quantify the magnitude and location of bone volume changes followed by histological analyses to assess bone repair. CAM blood vessels were observed to infiltrate the human bone cylinder and maintain human cell viability. Histological evaluation revealed extensive extracellular matrix deposition in proximity to endochondral condensations (Sox9+) on the CAM-implanted bone cylinders, correlating with a significant increase in bone volume by ?CT analysis (p?<?0.01). This human-avian system offers a simple refinement model for animal research and a step towards a humanized in vivo model for tissue engineering

What's all this hype about hypertext?: Teaching literature with George P. Landow's The Dickens Web

The essay describes the use of George P. Landow's hypertext, The Dickens Web, in an advanced undergraduate literature class and analyzes its practical and theoretical implications. Hypertext is shown to encourage active student engagement, especially with contextual material; to lead to more focused research topics; and to facilitate student collaboration. Some of Landow's claims about the ease with which this occurs, however, are questioned. The difficulty of teaching students how to follow and construct conceptual hypertextual links is examined, and the instructor's role in relation to student contributions to the Web is presented as much more problematic than Landow allows.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42572/1/10579_2004_Article_BF00419788.pd