3D printing of heart valves.

3D printing technologies have the potential to revolutionize the manufacture of heart valves through the ability to create bespoke, complex constructs. In light of recent technological advances, we review the progress made towards 3D printing of heart valves, focusing on studies that have utilised these technologies beyond manufacturing patient-specific moulds. We first overview the key requirements of a heart valve to assess functionality.

The role of Wnt signaling in mesenchymal stromal cell-driven angiogenesis.

Development, growth, and remodeling of blood vessels occur through an intricate process involving cell differentiation, proliferation, and rearrangement by cell migration under the direction of various signaling pathways. Recent reports highlight that resident and exogenous mesenchymal stromal cells (MSCs) have the potential to regulate the neovascularization process through paracrine secretion of proangiogenic factors. Recent research has established that the vasculogenic potential of MSCs is regulated by several signaling pathways, including the Wnt signaling pathway, and their interplay.

Using RNA-seq to identify suitable housekeeping genes for hypoxia studies in human adipose-derived stem cells.

Background: Hypoxic culture conditions have been used to study the impact of oxygen deprivation has on gene expression in a number of disease models. However, hypoxia response elements present in the promoter regions of some commonly used housekeeping genes, such as GAPDH and PGK1, can confound the relative gene expression analysis. Thus, there is ongoing debate as to which housekeeping gene is appropriate for studies investigating hypoxia-induced cell responses.

Novel hybrid biocomposites for tendon grafts: The addition of silk to polydioxanone and poly(lactide-co-caprolactone) enhances material properties, and biocompatibility.

Biopolymers play a critical role as scaffolds used in tendon and ligament (TL) regeneration. Although advanced biopolymer materials have been proposed with optimised mechanical properties, biocompatibility, degradation, and processability, it is still challenging to find the right balance between these properties. Here, we aim to develop novel hybrid biocomposites based on poly(-dioxanone) (PDO), poly(lactide-co-caprolactone) (LCL) and silk to produce high-performance grafts suitable for TL tissue repair.

Engineering Heart Valve Interfaces Using Melt Electrowriting: Biomimetic Design Strategies from Multi-Modal Imaging.

Interfaces within biological tissues not only connect different regions but also contribute to the overall functionality of the tissue. This is especially true in the case of the aortic heart valve. Here, melt electrowriting (MEW) is used to engineer complex, user-defined, interfaces for heart valve scaffolds.

Enhancing Resistance of Silk Fibroin Material to Enzymatic Degradation by Cross-Linking Both Crystalline and Amorphous Domains.

Silk fibroin (SF) membranes are finding widespread use as biomaterial scaffolds in a range of tissue engineering applications. The control over SF scaffold degradation kinetics is usually driven by the proportion of SF crystalline domains in the formulation, but membranes with a high β-sheet content are brittle and still contain amorphous domains, which are highly susceptible to enzymatic degradation. In this work, photo-cross-linking of SF using a ruthenium-based method, and with the addition of glycerol, was used to generate robust and flexible SF membranes for long-term tissue engineering applications requiring slow degradation of the scaffolds.

Usher Syndrome: Genetics and Molecular Links of Hearing Loss and Directions for Therapy.

Usher syndrome (USH) is an autosomal recessive (AR) disorder that permanently and severely affects the senses of hearing, vision, and balance. Three clinically distinct types of USH have been identified, decreasing in severity from Type 1 to 3, with symptoms of sensorineural hearing loss (SNHL), retinitis pigmentosa (RP), and vestibular dysfunction. There are currently nine confirmed and two suspected USH-causative genes, and a further three candidate loci have been mapped.

Tunable Biodegradable Silk-Based Memory Foams with Controlled Release of Antibiotics.

Sustained, local delivery of the antibiotic ciprofloxacin under different formats from porous silk protein-based memory foam systems was studied. Similarly, protease XIV was incorporated during processing to provide control of the degradation kinetics of the silk materials. In vitro antibiotic release studies combined with degradation assessments were utilized to assess the mechanisms and kinetics of release from the silk materials.

Protein Paper from Exfoliated Eri Silk Nanofibers.

The exfoliation of silk fiber is an attractive method to produce silk micro- and nanofibers that retain the secondary structure of native silk. However, most fibrillation methods used to date require the use of toxic and/or expensive solvents and the use of high energy. This study describes a low cost, scalable method to produce microfibrillated silk nanofibers without the use of toxic chemicals by controlling the application of shear using commercially scalable milling and homogenization equipment.

Silk particles, microfibres and nanofibres: A comparative study of their functions in 3D printing hydrogel scaffolds.

Silk, with highly crystalline structure and well-documented biocompatibility, is promising to be used as reinforcing material and build functionalized composite scaffolds. In the present study, we developed chitosan/silk composite scaffolds using silk particles, silk microfibres and nanofibres via 3D printing method. The three forms of silk fillers with varied shapes and dimensions were obtained via different processing methods and evaluated of their morphology, crystalline structure and thermal property.

Isolation of Epidermal Progenitor Cells from Rat Tympanic Membrane.

The eardrum is an important structural component for hearing, but it is delicate and subject to traumatic injury and disease. Healing mechanisms are activated after injury but sometimes healing fails and chronic perforations develop, requiring surgical intervention. To model the wound healing responses we established a simple method for isolating keratinocytes and progenitors from individual eardrums.

Generation of two induced pluripotent stem cell lines from a patient with compound heterozygous mutations in the USH2A gene.

The human iPSC lines LEIi010-A and LEIi010-B were generated from the dermal fibroblasts of a patient with Usher syndrome using episomal plasmids containing OCT4, SOX2, KLF4, L-MYC, LIN28, mir302/367 microRNA and shRNA for p53. These iPSC lines carry compound heterozygous mutations (c.949C > A and c.

Facile and versatile solid state surface modification of silk fibroin membranes using click chemistry.

Reported is a fast and versatile protocol to surface modify pre-cast silk membranes targeting tyrosine residues. Enriched alkyne silk membranes were prepared using this method and azides possessing a range of functional groups were tethered to the membrane surface using click chemistry to give a range of water contact angles from 85 ± 3° to 34 ± 6°.

Novel non-angiogenic role for mesenchymal stem cell-derived vascular endothelial growth factor on keratinocytes during wound healing.

With chronic wounds remaining a substantial healthcare issue, new therapies are sought to improve patient outcomes. Various studies have explored the benefits of promoting angiogenesis in wounds by targeting proangiogenic factors such as Vascular Endothelial Growth Factor (VEGF) family members to improve wound healing. Along similar lines, Mesenchymal Stem Cell (MSC) secretions, usually containing VEGF, have been used to improve angiogenesis in wound healing via a paracrine mechanism.

3D Printing of Silk Particle-Reinforced Chitosan Hydrogel Structures and Their Properties.

Hydrogel bioprinting is a major area of focus in the field of tissue engineering. However, 3D printed hydrogel scaffolds often suffer from low printing accuracy and poor mechanical properties because of their soft nature and tendency to shrink. This makes it challenging to process them into structural materials.

Optical Coherence Tomography of the Tympanic Membrane and Middle Ear: A Review.

Objective To evaluate the recent developments in optical coherence tomography (OCT) for tympanic membrane (TM) and middle ear (ME) imaging and to identify what further development is required for the technology to be integrated into common clinical use. Data Sources PubMed, Embase, Google Scholar, Scopus, and Web of Science. Review Methods A comprehensive literature search was performed for English language articles published from January 1966 to January 2018 with the keywords "tympanic membrane or middle ear,""optical coherence tomography," and "imaging.

The Influence of Breast Tumour-Derived Factors and Wnt Antagonism on the Transformation of Adipose-Derived Mesenchymal Stem Cells into Tumour-Associated Fibroblasts.

Within the tumour stroma, a heterogeneous population of cell types reciprocally regulates cell proliferation, which considerably affects the progression of the disease. In this study, using tumour conditioned medium (TCM) derived from breast tumour cell lines - MCF7 and MDA MB 231, we have demonstrated the differentiation of adipose-derived mesenchymal stem cells (ADSCs) into tumour-associated fibroblasts (TAFs). Since the Wnt signalling pathway is a key signalling pathway driving breast tumour growth, the effect of the Wnt antagonist secreted frizzled-related protein 4 (sFRP4) was also examined.

A novel microsurgical rodent model for the transplantation of engineered cardiac muscle flap.

Background: The survival of engineered cardiac muscle 'grafts' to the epicardium is limited by vascularization post-transplantation in rat models. In this article, we describe the methodology of a novel rat model that allows for the transplantation of an engineered cardiac muscle flap (ECMF) onto the epicardium.

Materials And Methods: A total of 40 rats were used.

Transcription and microRNA Profiling of Cultured Human Tympanic Membrane Epidermal Keratinocytes.

The human tympanic membrane (TM) has a thin outer epidermal layer which plays an important role in TM homeostasis and ear health. The specialised cells of the TM epidermis have a different physiology compared to normal skin epidermal keratinocytes, displaying a dynamic and constitutive migration that maintains a clear TM surface and assists in regeneration. Here, we characterise and compare molecular phenotypes in keratinocyte cultures from TM and normal skin.

Tympanic Membrane Derived Stem Cell-Like Cultures for Tissue Regeneration.

Epidermal cells with stem cell-like characteristics have been identified in the tympanic membrane (TM) and localized specifically to the umbo and annulus regions. While they have been proposed to play a role in the regeneration of both acute and chronic TM perforations, evidence for the mechanism and regulation of their contribution is not yet described. Indeed, the behavior of these putative stem cells is largely unknown, in part due to a lack of refined methods for efficient cell isolation.

Mechanical behaviour of alginate-gelatin hydrogels for 3D bioprinting.

Hydrogels comprised of alginate and gelatin have demonstrated potential as biomaterials in three dimensional (3D) bioprinting applications. However, as with all hydrogel-based biomaterials used in extrusion-based bioprinting, many parameters influence their performance and there is limited data characterising the behaviour of alginate-gelatin (Alg-Gel) hydrogels. Here we investigated nine Alg-Gel blends by varying the individual constituent concentrations.

The inhibitory influence of adipose tissue-derived mesenchymal stem cell environment and Wnt antagonism on breast tumour cell lines.

Tumours exhibit a heterogeneous mix of cell types that reciprocally regulate their growth in the tumour stroma, considerably affecting the progression of the disease. Both adipose-derived mesenchymal stem cells and Wnt signalling pathway are vital in driving breast tumour growth. Hence, we examined the effect of secreted factors released by adipose-derived mesenchymal stem cells, and further explored the anti-tumour property of the Wnt antagonist secreted frizzled-related protein 4 (sFRP4) on MCF-7 and MDA-MB-231 breast tumour cells.

Addressing the cost of infractions in the online literature and databases.

Myocardial infarction sometimes appears misspelt as myocardial infraction in the cardiovascular research literature. With accurate citation of literature contributions important to advancing the field and its contributors, in this study we aimed to document the frequency and explore the causes and impact of this error specific to the cardiology literature. Literature databases (PubMed, Scopus, Web of Science, WIPO, Google Scholar, Google) were searched to identify the rate of myocardial infraction errors and found an error rate between 0.