Temporal mechanically-induced signaling events in bone and dorsal root ganglion neurons after in vivo bone loading

Mechanical signals play an integral role in the regulation of bone mass and functional adaptation to bone loading. The osteocyte has long been considered the principle mechanosensory cell type in bone, although recent evidence suggests the sensory nervous system may play a role in mechanosensing. The specific signaling pathways responsible for functional adaptation of the skeleton through modeling and remodeling are not clearly defined. In vitro studies suggest involvement of intracellular signaling through mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt), and mammalian target of rapamycin (mTOR). However, anabolic signaling responses to bone loading using a whole animal in vivo model have not been studied in detail. Therefore, we examined mechanically-induced signaling events at five time points from 0 to 24 hours after loading using the rat in vivo ulna end-loading model. Western blot analysis of bone for MAPK's, PI3K/Akt, and mTOR signaling, and quantitative reverse transcription polymerase chain reaction (qRT-PCR) to estimate gene expression of calcitonin gene-related protein alpha (CGRP-α), brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), c-jun, and c-fos in dorsal root ganglion (DRG) of the brachial intumescence were performed. There was a significant increase in signaling through MAPK's including extracellular signal-related kinase (ERK) and c-Jun N-terminal kinase (JNK) in loaded limbs at 15 minutes after mechanical loading. Ulna loading did not significantly influence expression of the genes of interest in DRG neurons. Bone signaling and DRG gene expression from the loaded and contralateral limbs was correlated (SR>0.40, P<0.05). However, bone signaling did not correlate with expression of the genes of interest in DRG neurons. These results suggest that signaling through the MAPK pathway may be involved in load-induced bone formation in vivo. Further characterization of the molecular events involved in regulation of bone adaptation is needed to understand the timing and impact of loading events, and the contribution of the neuronal signaling to functional adaptation of bone

LCP external fixation - External application of an internal fixator: two cases and a review of the literature

The locking compression plate (LCP) is an angle-stable fixator intended for intracorporeal application. In selected cases, it can be applied externally in an extracorporeal location to function as a monolateral external fixator. We describe one patient with Schatzker V tibial plateau fracture and one patient with Gustillo IIIB open tibia shaft fracture treated initially with traditional external fixation for whom exchange fixation with externally applied LCPs was performed. The first case went on to bony union while the second case required bone grafting for delayed union. Both patients found that the LCP external fixators facilitated mobilization and were more manageable and aesthetically acceptable than traditional bar-Schanz pin fixators

Improved healing response in delayed unions of the tibia with low-intensity pulsed ultrasound: results of a randomized sham-controlled trial

<p>Abstract</p> <p>Background</p> <p>We compared the healing response of tibial delayed unions between subjects treated with low-intensity pulsed ultrasound (LIPUS) (n = 51) and subjects treated with a sham device (n = 50). Fracture age was ≥ 4 months in all cases. Study personnel and participants were blinded to random treatment assignment throughout the study.</p> <p>Methods</p> <p>This multi-center randomized sham-controlled trial was undertaken at six hospitals in Germany. Adult patients who had sustained a tibial shaft fracture that subsequently showed inadequate progress toward healing (i.e., delayed union) were enrolled and randomized to receive either LIPUS (Exogen 2000/2000+, Smith & Nephew GmbH, Schenefeld, Germany) or an identical nonoperative sham device. The daily treatment duration was 20 minutes, for a period of 16 weeks. Subjects randomly assigned to active treatment had the ultrasound pressure wave signal set at the following parameters: 1.5 MHz frequency, 1 kHz repetition rate, 200 μs pulse duration, 30 mW/cm²spatial intensity. Progress toward healing was estimated from changes in bone mineral density (BMD) and gap area as determined from computed tomography scans. Intention-to-treat analysis was conducted using a multiple imputation methodology.</p> <p>Results</p> <p>Based on log-transformed data, mean improvement in BMD was 1.34 (90% confidence interval (CI) 1.14 to 1.57) times greater for LIPUS-treated subjects compared to sham (p = 0.002). A mean reduction in bone gap area also favored LIPUS treatment (p = 0.014).</p> <p>Conclusions</p> <p>These findings demonstrate significantly greater progress toward bone healing after LIPUS treatment compared to no LIPUS treatment in subjects with established delayed unions of the tibia.</p

Effective, Robust Design of Community Mitigation for Pandemic Influenza: A Systematic Examination of Proposed US Guidance

BACKGROUND: The US government proposes pandemic influenza mitigation guidance that includes isolation and antiviral treatment of ill persons, voluntary household member quarantine and antiviral prophylaxis, social distancing of individuals, school closure, reduction of contacts at work, and prioritized vaccination. Is this the best strategy combination? Is choice of this strategy robust to pandemic uncertainties? What are critical enablers of community resilience? METHODS AND FINDINGS: We systematically simulate a broad range of pandemic scenarios and mitigation strategies using a networked, agent-based model of a community of explicit, multiply-overlapping social contact networks. We evaluate illness and societal burden for alterations in social networks, illness parameters, or intervention implementation. For a 1918-like pandemic, the best strategy minimizes illness to <1% of the population and combines network-based (e.g. school closure, social distancing of all with adults' contacts at work reduced), and case-based measures (e.g. antiviral treatment of the ill and prophylaxis of household members). We find choice of this best strategy robust to removal of enhanced transmission by the young, additional complexity in contact networks, and altered influenza natural history including extended viral shedding. Administration of age-group or randomly targeted 50% effective pre-pandemic vaccine with 7% population coverage (current US H5N1 vaccine stockpile) had minimal effect on outcomes. In order, mitigation success depends on rapid strategy implementation, high compliance, regional mitigation, and rigorous rescinding criteria; these are the critical enablers for community resilience. CONCLUSIONS: Systematic evaluation of feasible, recommended pandemic influenza interventions generally confirms the US community mitigation guidance yields best strategy choices for pandemic planning that are robust to a wide range of uncertainty. The best strategy combines network- and case-based interventions; network-based interventions are paramount. Because strategies must be applied rapidly, regionally, and stringently for greatest benefit, preparation and public education is required for long-lasting, high community compliance during a pandemic

Intranasal Immunization with an Archaeal Lipid Mucosal Vaccine Adjuvant and Delivery Formulation Protects against a Respiratory Pathogen Challenge

Archaeal lipid mucosal vaccine adjuvant and delivery (AMVAD) is a safe mucosal adjuvant that elicits long lasting and memory boostable mucosal and systemic immune responses to model antigens such as ovalbumin. In this study, we evaluated the potential of the AMVAD system for eliciting protective immunity against mucosal bacterial infections, using a mouse model of intranasal Francisella tularensis LVS (LVS) challenge. Intranasal immunization of mice with cell free extract of LVS (LVSCE) adjuvanted with the AMVAD system (LVSCE/AMVAD) induced F. tularensis-specific antibody responses in sera and bronchoalveolar lavage fluids, as well as antigen-specific splenocyte proliferation and IL-17 production. More importantly, the AMVAD vaccine partially protected the mice against a lethal intranasal challenge with LVS. Compared to LVSCE immunized and naïve mice, the LVSCE/AMVAD immunized mice showed substantial to significant reduction in pathogen burdens in the lungs and spleens, reduced serum and pulmonary levels of proinflammatory cytokines/chemokines, and longer mean time to death as well as significantly higher survival rates (p<0.05). These results suggest that the AMVAD system is a promising mucosal adjuvant and vaccine delivery technology, and should be explored further for its applications in combating mucosal infectious diseases

Occurrence and Treatment of Bone Atrophic Non-Unions Investigated by an Integrative Approach

Recently developed atrophic non-union models are a good representation of the clinical situation in which many nonunions develop. Based on previous experimental studies with these atrophic non-union models, it was hypothesized that in order to obtain successful fracture healing, blood vessels, growth factors, and (proliferative) precursor cells all need to be present in the callus at the same time. This study uses a combined in vivo-in silico approach to investigate these different aspects (vasculature, growth factors, cell proliferation). The mathematical model, initially developed for the study of normal fracture healing, is able to capture essential aspects of the in vivo atrophic non-union model despite a number of deviations that are mainly due to simplifications in the in silico model. The mathematical model is subsequently used to test possible treatment strategies for atrophic non-unions (i.e. cell transplant at post-osteotomy, week 3). Preliminary in vivo experiments corroborate the numerical predictions. Finally, the mathematical model is applied to explain experimental observations and identify potentially crucial steps in the treatments and can thereby be used to optimize experimental and clinical studies in this area. This study demonstrates the potential of the combined in silico-in vivo approach and its clinical implications for the early treatment of patients with problematic fractures

The Involvement of IL-17A in the Murine Response to Sub-Lethal Inhalational Infection with Francisella tularensis

Background: Francisella tularensis is an intercellular bacterium often causing fatal disease when inhaled. Previous reports have underlined the role of cell-mediated immunity and IFNc in the host response to Francisella tularensis infection. Methodology/Principal Findings: Here we provide evidence for the involvement of IL-17A in host defense to inhalational tularemia, using a mouse model of intranasal infection with the Live Vaccine Strain (LVS). We demonstrate the kinetics of IL-17A production in lavage fluids of infected lungs and identify the IL-17A-producing lymphocytes as pulmonary cd and Th17 cells. The peak of IL-17A production appears early during sub-lethal infection, it precedes the peak of immune activation and the nadir of the disease, and then subsides subsequently. Exogenous airway administration of IL-17A or of IL-23 had a limited yet consistent effect of delaying the onset of death from a lethal dose of LVS, implying that IL-17A may be involved in restraining the infection. The protective role for IL-17A was directly demonstrated by in vivo neutralization of IL-17A. Administration of anti IL-17A antibodies concomitantly to a sub-lethal airway infection with 0.16LD50 resulted in a fatal disease. Conclusion: In summary, these data characterize the involvement and underline the protective key role of the IL-17A axis in the lungs from inhalational tularemia

Characterization of a rat osteotomy model with impaired healing

<p>Abstract</p> <p>Background</p> <p>Delayed union or nonunion are frequent and feared complications in fracture treatment. Animal models of impaired bone healing are rare. Moreover, specific descriptions are limited although understanding of the biological course of pathogenesis of fracture nonunion is essential for therapeutic approaches.</p> <p>Methods</p> <p>A rat tibial osteotomy model with subsequent intramedullary stabilization was performed. The healing progress of the osteotomy model was compared to a previously described closed fracture model. Histological analyses, biomechanical testing and radiological screening were undertaken during the observation period of 84 days (d) to verify the status of the healing process. In this context, particular attention was paid to a comparison of bone slices by histological and immunohistological (IHC) methods at early points in time, <it>i.e</it>. at 5 and 10 d post bone defect.</p> <p>Results</p> <p>In contrast to the closed fracture technique osteotomy led to delayed union or nonunion until 84 d post intervention. The dimensions of whole reactive callus and the amounts of vessels in defined regions of the callus differed significantly between osteotomized and fractured animals at 10 d post surgery. A lower fraction of newly formed bone and cartilaginous tissue was obvious during this period in osteotomized animals and more inflammatory cells were observed in the callus. Newly formed bone tissue accumulated slowly on the anterior tibial side with both techniques. New formation of reparative cartilage was obviously inhibited on the anterior side, the surgical approach side, in osteotomized animals only.</p> <p>Conclusion</p> <p>Tibial osteotomy with intramedullary stabilisation in rats leads to pronounced delayed union and nonunion until 84 d post intervention. The early onset of this delay can already be detected histologically within 10 d post surgery. Moreover, the osteotomy technique is associated with cellular and vascular signs of persistent inflammation within the first 10 d after bone defect and may be a contributory factor to impaired healing. The model would be excellent to test agents to promote fracture healing.</p

Plant biosystems design research roadmap 1.0

Human life intimately depends on plants for food, biomaterials, health, energy, and a sustainable environment. Various plants have been genetically improved mostly through breeding, along with limited modification via genetic engineering, yet they are still not able to meet the ever-increasing needs, in terms of both quantity and quality, resulting from the rapid increase in world population and expected standards of living. A step change that may address these challenges would be to expand the potential of plants using biosystems design approaches. This represents a shift in plant science research from relatively simple trial-and-error approaches to innovative strategies based on predictive models of biological systems. Plant biosystems design seeks to accelerate plant genetic improvement using genome editing and genetic circuit engineering or create novel plant systems through de novo synthesis of plant genomes. From this perspective, we present a comprehensive roadmap of plant biosystems design covering theories, principles, and technical methods, along with potential applications in basic and applied plant biology research. We highlight current challenges, future opportunities, and research priorities, along with a framework for international collaboration, towards rapid advancement of this emerging interdisciplinary area of research. Finally, we discuss the importance of social responsibility in utilizing plant biosystems design and suggest strategies for improving public perception, trust, and acceptance