BIOFABRICATION OF SCAFFOLDS FOR INTERVERTEBRAL DISC (IVD) TISSUE REGENERATION

The ultimate goal of tissue regeneration is to replace damaged or diseased tissue with a cell-based or biomaterial-based tissue that accurately mimics the functionality, biology, mechanics, and cellular and extracellular matrix (ECM) composition of the native tissue. Specifically, the ability to control the architecture of tissue engineered constructs plays a vital role in all of these issues as scaffold architecture has an affect on function, biomechanics, and cellular behavior. Many tissue engineered scaffolds focus on the ability to mimic natural tissue by simulating the ECM due to the fact that in each distinct tissue, the ECM serves as a structural component by providing unique mechanical strength as well as regions for cellular attachment or the storage of a variety of biomolecules. Additionally, cellular behavior has the ability to be controlled based on the structure and composition of the ECM. More specifically, matrix has the ability to modulate a variety of cellular behaviors such as: adhesion, morphology, migration, proliferation, and differentiation while also controlling the ability of cells to produce and synthesize ECM with similar characteristics to that of surrounding tissue. Tissue matrix and structure plays an essential role during the process of tissue formation, remodeling, and regeneration. The ability to mimic native tissue ECM using various biofabrication-based techniques has become an emerging concept in the realm of tissue regeneration. Biofabrication utilizes automated computer-aided-design (CAD) and computer-controlled technologies to create reproducible biomaterial and cell-based scaffolds that have the ability to imitate native tissue ECM. Of particular interest are strategies that employ biofabrication with the aim of improving the overall control over scaffold architecture and microstructure while also providing reproducibility. Due to their versatility, a variety of promising biofabrication strategies exist, including rapid prototyping methods such as bioprinting and additive manufacturing, which rely on the deposition or extrusion of materials. Using these methods, a multitude of materials can be easily used to fabricate scaffold structures with various morphologies. However, the potential of many biofabrication methods in tissue engineering applications is limited by the potential resolution of the structures that can be created. It was our goal to investigate a unique biofabrication strategy with the aim of fabricating 3-D scaffolds at a high resolution with morphological, biological, and mechanical properties similar to those of natural intervertebral discs (IVDs). Initially, a CAD-based biofabrication approach was developed and systematically optimized. This method was selected to utilize a custom-designed computer interface with 3-D motion control that allowed for greater resolution and precision of the fabricated scaffold architecture. Furthermore, we incorporated a temperature controlled polymer collection stage, which proved advantageous in enhancing the resolution of the biofabrication technique. By lowering the temperature of the collecting stage below the freezing point of the polymer solution, it was discovered that the extruded polymer solution could be solidified directly as it exited the micropipette extrusion tip through an increase in viscosity. Results from initial studies provided valuable clues towards determining the relationship between motor speeds, polymer solution temperatures, micropipette size, extrusion rate, and polymer solution viscosity. These results encouraged the investigation of the ability to use this method to precisely control scaffold spatial orientation for the fabrication of IVD scaffolds. Since previous IVD scaffold fabrication methods have not effectively accounted for the inadequacies of spinal fusion and artificial disc replacement in the treatment of a degenerated disc, we addressed the significance of matching native tissue histology and biomechanics by using fabricated scaffolds that closely mimic natural IVD tissue. The annulus fibrosus (AF), or outer region of the IVD, was the focus of this project due to current and previous challenges in recreating its discrete tissue architecture, which is not an issue for the inner nucleus pulposus (NP) region, as it is more commonly mimicked with the use of a hydrogel-based biomaterial. Multiple elastomeric materials, including biocompatible and biodegradable polyurethane (PU) and chitosan-gelatin (CS/GEL), were investigated to evaluate the usefulness of this biofabrication approach to create biomimetic IVD scaffolds utilizing various materials. It was determined that the biofabrication method enabled the use of multiple materials and that the fabricated scaffolds were able to mimic the kidney shaped structure of the IVD. Additionally, the scaffolds exhibited ideal concentric lamellar thickness and spacing, accurately mimicking the native structure of the AF in the human IVD. To the best of our knowledge, these accomplishments in recreating the native AF histological architecture within tissue engineered constructs have not been achieved elsewhere. Cells attached and aligned on the scaffolds in the direction of the concentric lamellar structure, emulating cell behavior comparable to the native AF. These 3-D scaffolds exhibited ideal elastic properties and did not experience permanent deformation under dynamic loading. Additionally, the scaffold mechanical properties showed no significant differences when compared with native human IVD tissue. The scaffolding promoted chondrocyte cell attachment and proliferation in alignment with the concentric lamellae, proving this method improves upon current IVD scaffold fabrication approaches, as it takes into account native tissue structure and cell response. To expand upon these findings, the biomimetic IVD scaffolds were investigated to analyze the formation of 3-D cellularized tissue. 3-D multicellular spheroids formed from chondrocytes were incorporated within the scaffold to fully cellularize the void spacing within the IVD scaffold lamellae. The ability of this 3-D cellularized structure to emulate native IVD tissue was then further analyzed by evaluating the ability of the scaffolds to synthesize matrix that was structurally and compositionally similar to that of native tissue. Our studies indicate that the 3-D cellularized IVD constructs accurately mimic native IVD tissue and provide not only a scaffold, but a cellularized platform to promote tissue regeneration. Future studies will assess the biofabricted IVD structures for tissue regeneration and biostability using in vivo rodent subcutaneous animal models

The repositioning of epigenetic probes/inhibitors identifies new anti-schistosomal lead compounds and chemotherapeutic targets

Article Authors Metrics Comments Media Coverage Peer Review Abstract Author summary Introduction Materials and methods Results and discussion Supporting information Acknowledgments References Reader Comments (0) Media Coverage (0) Figures Abstract Background Praziquantel represents the frontline chemotherapy used to treat schistosomiasis, a neglected tropical disease (NTD) caused by infection with macro-parasitic blood fluke schistosomes. While this drug is safe, its inability to kill all schistosome lifecycle stages within the human host often requires repeat treatments. This limitation, amongst others, has led to the search for novel anti-schistosome replacement or combinatorial chemotherapies. Here, we describe a repositioning strategy to assess the anthelmintic activity of epigenetic probes/inhibitors obtained from the Structural Genomics Consortium. Methodology/Principle findings Thirty-seven epigenetic probes/inhibitors targeting histone readers, writers and erasers were initially screened against Schistosoma mansoni schistosomula using the high-throughput Roboworm platform. At 10 μM, 14 of these 37 compounds (38%) negatively affected schistosomula motility and phenotype after 72 hours of continuous co-incubation. Subsequent dose-response titrations against schistosomula and adult worms revealed epigenetic probes targeting one reader (NVS-CECR2-1), one writer (LLY-507 and BAY-598) and one eraser (GSK-J4) to be particularly active. As LLY-507/BAY-598 (SMYD2 histone methyltransferase inhibitors) and GSK-J4 (a JMJD3 histone demethylase inhibitor) regulate an epigenetic process (protein methylation) known to be critical for schistosome development, further characterisation of these compounds/putative targets was performed. RNA interference (RNAi) of one putative LLY-507/BAY-598 S. mansoni target (Smp_000700) in adult worms replicated the compound-mediated motility and egg production defects. Furthermore, H3K36me2, a known product catalysed by SMYD2 activity, was also reduced by LLY-507 (25%), BAY-598 (23%) and siSmp_000700 (15%) treatment of adult worms. Oviposition and packaging of vitelline cells into in vitro laid eggs was also significantly affected by GSK-J4 (putative cell permeable prodrug inhibitor of Smp_034000), but not by the related structural analogue GSK-J1 (cell impermeable inhibitor). Conclusion/Significance Collectively, these results provide further support for the development of next-generation drugs targeting schistosome epigenetic pathway components. In particular, the progression of histone methylation/demethylation modulators presents a tractable strategy for anti-schistosomal control

Impacts of UVB provision on serum vitamin D3, pigmentation, growth rates and total body mineral content in Mallorcan midwife toad larvae (Alytes muletensis)

The health of amphibians in captive breeding programmes can be compromised by nutritional metabolic bone disease and secondary hyperparathyroidism, which is a result of poor calcium metabolism or an inverse calcium:phosphorus ratio in the blood. UVB provision allows for cutaneous photobiosynthesis of vitamin D3, which is needed for adequate absorption of calcium from the diet, and so many post-metamorphic anurans are routinely provided with UVB radiation in captivity; however, tadpoles are not. This is the first study of its kind to investigate the effect of UVB radiation provision for anuran larvae from a captive husbandry perspective. This study examines the effects of ecologically appropriate levels of UVB exposure on growth rates, pigmentation acquisition, serum vitamin levels in the blood plasma, and whole-body mineral content in the Mallorcan midwife toad (Alytes muletensis). There were no significant effects of UVB exposure on any parameters measured. This may be because UVB radiation is simply not required by the larvae of this species, or because the provision of UVB radiation alone is not sufficient for its use in calcium metabolism. Further research is needed to elucidate how tadpoles interact with UVB radiation in nature and to examine how UVB radiation is provided in captivity and test for effects using a wider variety of species from a range of different habitats

Beauty in Disability: An Aesthetics for Dance and for Life

To what extent does dance contribute to an ideal of beauty that can enrich human quality of life? To what extent are standards of beauty predicated on an ideal human body that has no disability? In this chapter, we show how conceptions of proportionality, perfection, and ethereality from the Ancient Greeks through the 19th century can still be seen today in some kinds of dance, particularly in ballet. Disability studies and disability-inclusive dance companies, however, have started to change this. The disabled person can be beautiful, we will show, in dance and in life, under a disability aesthetics that follows Edmund Burke (1730-1797) and that suggests an alternative standard of beauty, which we call “beauty-in-experience,” where beauty is perceived in the qualitative experience of abled and disabled dancers moving together in dance.https://ecommons.udayton.edu/books/1023/thumbnail.jp

Writing in Britain and Ireland, c. 400 to c. 800

No abstract available

Values, attributes and practices of dance artists in inclusive dance talent development contexts

There is a paucity of research focused on understanding the qualities which underpin dance artists’ practice in working with talented young dancers with disabilities. This study investigated what informs how dance artists work in inclusive dance talent development contexts. Four dance class observations were conducted to provide evidence of dance artists’ qualities in practice. Six dance artists participated in semi-structured interviews. Thematic data analysis revealed four categories: the dance persona; values; attributes; and practices of dance artists. The dance persona was typified by characteristics such as being human, humility, altruism, and confidence. Artists’ values and attributes included celebrating difference, aspiring towards equality and relationality. Their practices were exemplified by varied differentiation strategies and an emphasis on reflection. These findings provide new insight into what drives artists working with dancers with and without disabilities, and aids better understanding of best practice in this context

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Neurophysiological abnormalities in multiple sclerosis: Disease process or functional compensation?

Background: Intracortical inhibition is reduced in patients with multiple sclerosis. The cause and implications of this change are unknown: it may result from damage within inhibitory systems or, alternatively, may represent compensatory downregulation of cortical inhibition.Objective: To examine the association between measures of intracortical inhibition and motor and cognitive abilities in patients with multiple sclerosis.Methods: 36 patients with the relapsing-remitting form of multiple sclerosis were recruited from a specialty clinic and underwent evaluation of motor and cognitive ability using the Multiple Sclerosis Functional Composite scale. Cortical silent period (cSP) and short-interval intracortical inhibition (sICI) were measured in both hemispheres using transcranial magnetic stimulation. 13 healthy controls were evaluated on the same measures. We calculated correlations between functional and neurophysiological outcomes, and evaluated hemispheric asymmetries.Results: Patients with remitting MS have significantly longer cSP durations (101.6±29.2msec) than healthy controls (82.2±22.4ms, t(47)=-2.166, p=0.035), indicating increased intracortical inhibition. Greater inhibition is associated with worse hand function as measured by the nine-hole peg test (dominant hand: ρ=0.360, p=0.031; non-dominant hand: ρ=0.351, p=0.039). Overall, cSP duration is comparable between cerebral hemispheres within the patient group (t(69)=0.633, p=0.529). However, among patients with significant hemispheric asymmetry for cSP duration, the direction of this asymmetry predicts asymmetry for hand function (ρ=0.950, p<0.001). Conclusion: These results support the hypothesis that alterations in cortical excitability in patients with MS reflect damage to inhibitory systems. In the context of earlier findings, our results also indicate that cortical excitability may change with respect to disease stage, and that the mechanisms underlying these changes may differ depending on stage. We cannot rule out the possibility that decreases in cortical excitability during the relapsing phase or in other subtypes of MS may be compensatory. Taking into account neurophysiological markers such as cSP may be useful in predicting disease severity.Historique: Les mesures d'inhibition intracorticale sont réduites chez les patients atteints de sclérose en plaques. La cause et les implications de ces changements sont inconnues : cela peut résulter d'un dommage dans les systèmes d'inhibition ou, alternativement, peut représenter des régulations descendantes compensatoires de l'inhibition corticale.Objectif: Pour examiner l'association entre les mesures de l'inhibition intracorticale et les habiletés cognitives et motrices chez les patients atteints de sclérose en plaques.Méthodes: 36 patients ayant une forme de sclérose en plaques récurrente-rémittente ont été recrutés par une clinique spécialisée et ont subi une évaluation de leur habiletés motrices et cognitives en utilisant l'Échelle de composé fonctionnel de la sclérose en plaques. Des périodes de silence cortical (PSc) et l'inhibition intracorticale de court intervalle (IIcI) furent mesurées dans les deux hémisphères en utilisant la stimulation transcrânienne magnétique. 13 sujets normaux ont également été évalués avec les mêmes mesures. Nous avons calculé les corrélations entre les résultats fonctionnels et neurophysiologiques, et avons évalué les asymétries hémisphériques. Résultats: Les patients avec une sclérose en plaques rémittente possèdent des PSc d'une durée significativement plus longue (101.6±29.2msec) que les sujets normaux (82.2±22.4ms, t(47)=-2.166, p=0.035), ce qui indique une augmentation de l'inhibition intracorticale. Une inhibition plus grande est associée avec des fonctions manuelles moins bonnes telles que mesurées par le test de dextérité manuelle de neuf-trous (main dominante: ρ=0.360, p=0.031; main non-dominante : ρ=0.351, p=0.039). Généralement, la durée PSc est comparable entre les hémisphères cérébraux dans le groupe de patients (t(69)=0.633, p=0.529). Cependant, parmi les patients ayant une asymétrie hémisphérique significative pour la durée des PSc, la direction de cette asymétrie prédit une asymétrie pour la fonction manuelle (ρ=0.950, p<0.001). Conclusion: Ces résultats supportent l'hypothèse que les changements dans l'inhibition corticale chez les patients atteints de sclérose en plaques reflètent le dommage des systèmes inhibitoires. Dans le contexte de nos découvertes précédentes, nos résultats indiquent également que l'inhibition corticale pourrait changer en ce qui concerne le stade de la maladie, et que les mécanismes reliés à ces changements pourraient différer dépendamment du stade. Nous ne pouvons omettre la possibilité que la augmentation de l'inhibition corticale durant la phase récurrente ou autre sous-forme de SP puisse être compensatoire. Il pourrait être utile de prendre en considération les marqueurs neurophysiologiques tels que la PSc afin de prédire la sévérité de la maladie