Metallomic mapping of gut and brain in heavy metal exposed earthworms: A novel paradigm in ecotoxicology.

This study explored the uptake of lead in the epigeic earthworm Dendrobaena veneta exposed to 0, 1000, and 2500 µg Pb/g soil. The soil metal content was extracted using strong acid digestion and water leaching, and analysed by means of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to estimate absolute and bioavailable concentrations of metals in the soil. The guts and heads of lead-exposed earthworms were processed into formalin-fixed and paraffin embedded sections for high-resolution multi-element metallomic imaging via Laser Ablation ICP-MS (LA-ICP-MS). Metallomic maps of phosphorus, zinc, and lead were produced at 15-µm resolution in the head and gut of D. veneta. Additional 4-µm resolution metallomic maps of the earthworm brains were taken, revealing the detailed localisation of metals in the brain. The Pb bioaccumulated in the chloragogenous tissues of the earthworm in a dose-dependent manner, making it possible to track the extent of soil contamination. The bioaccumulation of P and Zn in earthworm tissues was independent of Pb exposure concentration. This approach demonstrates the utility of LA-ICP-MS as a powerful approach for ecotoxicology and environmental risk assessments.

Bio-electrospraying 3-D Organotypic Human Skin Cultures.

Organotypic 3D tissue models have greatly contributed to understand a wide range of molecular and cellular characteristics within a functional or diseased tissue. Human skin reconstructs which act as models are most useful for a wide range of investigations, ranging from tissue engineering and regenerative medicine, drug development, screening, and discovery to name a few. There are many approaches for reconstructing 3D skin tissue models, however, to date there have been very few that are able to generate organotypic 3D constructs with a single technology having minimal processing steps to finally scalability. The many manifestations of 3D bioprinting have contributed to this endeavor, having said that, the technology's limitations have tempered those reconstructed models, as they are known to contain low cell numbers/concentrations to those having damaged/dead molecules/cells within the reconstructed tissue, which are not desirable, for exploring as tissues models. Contrary to 3D bioprinting approaches, bio-electrosprays have been demonstrated to possess the ability to handle large concentrations of cells and molecules to whole fertilized embryos without damaging them from a molecular level upwards. Consequently, this article demonstrates, for the first time, bio-electrospray's capacity to reconstruct skin-like structures in vitro and its potential in reconstructing full-thickness 3D organotypic human skin tissues.

Cell Electrospinning: Revolutionising Cell Scaffolding for Healthcare.

Electrospinning is a century-old technology, which has recently found its vast applicability to many areas of research and development and its utility in industry. In the context of the life and health sciences, electrospinning for many years has been explored as a unique approach to scaffolding, on which cells are manually or through automated means seeded with cells. Unfortunately, this approach has seen little being achieved, as the voids generated between fibers within a scaffold negate cell infiltration throughout the entire scaffold. This limitation is a bottleneck for electrospinning in its true applicability to the healthcare and medical sciences.

Bio-electrosprayed human neural stem cells are viable and maintain their differentiation potential.

Background: Bio-electrospray (BES) is a jet-based delivery system driven by an electric field that has the ability to form micro to nano-sized droplets. It holds great potential as a tissue engineering tool as it can be used to place cells into specific patterns. As the human central nervous system (CNS) cannot be studied in vivo at the cellular and molecular level, in vitro CNS models are needed. Human neural stem cells (hNSCs) are the CNS building block as they can generate both neurones and glial cells. Methods: Here we assessed for the first time how hNSCs respond to BES. To this purpose, different hNSC lines were sprayed at 10 kV and their ability to survive, grow and differentiate was assessed at different time points. Results: BES induced only a small and transient decrease in hNSC metabolic activity, from which the cells recovered by day 6, and no significant increase in cell death was observed, as assessed by flow cytometry. Furthermore, bio-electrosprayed hNSCs differentiated as efficiently as controls into neurones, astrocytes and oligodendrocytes, as shown by morphological, protein and gene expression analysis. Conclusions: This study highlights the robustness of hNSCs and identifies BES as a suitable technology that could be developed for the direct deposition of these cells in specific locations and configurations.

Reimagining Flow Cytometric Cell Sorting.

In this review, a brief history of this unrivaled technology, flow cytometry, is provided, highlighting its past and present advances, with particular focus on "flow cell" technologies. Flow cytometry has truly revolutionized high-throughput single cell analysis, which has tremendous implications, from laboratory to the clinic. This technology embodies what is truly referred to as cross fertile research, merging the physical with the life sciences. This review introduces the recent notable advancements in flow cell technology. This advancement sees the complete removal of liquid sheath flow, which has advanced the technology with the possibility of both the reduction in its foot print, while also simplifying the flow cells explored in cytometry. Interestingly, the novel sheathless flow cell technology demonstrated herein has the flexibility for handling both heterogeneous cell populations and whole organisms, thus demonstrating a versatile flow cell technology for both flow cytometry and fluorescent-activated cell sorting.

Anti-PD-1 immunotherapy leads to tuberculosis reactivation via dysregulation of TNF-α.

Previously, we developed a 3-dimensional cell culture model of human tuberculosis (TB) and demonstrated its potential to interrogate the host-pathogen interaction (Tezera et al., 2017a). Here, we use the model to investigate mechanisms whereby immune checkpoint therapy for cancer paradoxically activates TB infection. In patients, PD-1 is expressed in Mycobacterium tuberculosis (Mtb)-infected lung tissue but is absent in areas of immunopathology. In the microsphere model, PD-1 ligands are up-regulated by infection, and the PD-1/PD-L1 axis is further induced by hypoxia. Inhibition of PD-1 signalling increases Mtb growth, and augments cytokine secretion. TNF-α is responsible for accelerated Mtb growth, and TNF-α neutralisation reverses augmented Mtb growth caused by anti-PD-1 treatment. In human TB, pulmonary TNF-α immunoreactivity is increased and circulating PD-1 expression negatively correlates with sputum TNF-α concentrations. Together, our findings demonstrate that PD-1 regulates the immune response in TB, and inhibition of PD-1 accelerates Mtb growth via excessive TNF-α secretion.

General Computational Methodology for Modeling Electrohydrodynamic Flows: Prediction and Optimization Capability for the Generation of Bubbles and Fibers.

The application of an electric field on a fluid in motion gives rise to unique features and flow manipulation capabilities. Technologies ranging from bubble formation, droplet generation, fiber spinning, and many others are predicated on this type of flows, often referred to as Electrohydrodynamics (EHD). In this paper, we present a numerical methodology that allows for the modeling of such processes in a generalized way. The method can account for the premixing of various liquid species, the injection of gases in the mixture and the interaction of such complex multiphase flow with an electric field, static or AC. The domain in which these processes take place can be of arbitrary geometric complexity, allowing for design and optimization of complex EHD devices. Our study looks at the critical phases of some of these processes and emphasizes the strong coupling of fluid mechanics and electric fields and the influence of the electric field on fluid flow and vice versa. The conservation of mass and momentum, with appropriate additional force terms coming from the presence of the electric field, and the electrostatic equations are coupled together and solved using the Finite Volume method. The Volume of Fluid (VoF) technique is used to track free surfaces dynamically. The solution procedure iteratively computes electric body and surface forces and then includes those into the Navier-Stokes equation to predict the velocity field and other fluid parameters. No initial shape is assumed for the fluid(s) and charge distributions. The methodology presented handles two-dimensional, axisymmetric. and full three-dimensional cases of arbitrary geometric complexity, allowing for mixing and microfluidic configurations of high levels of realism. We highlight the capability of the method by demonstrating cases like the formation of a Taylor cone, microfluidic bubble generation, jet evolution, and droplet breakup. Results agree well with both existing experimental and computational reports.

Encapsulation of macrophages enhances their retention and angiogenic potential.

Cell therapies to treat critical limb ischaemia have demonstrated only modest results in clinical trials, and this has been partly attributed to poor cell retention following their delivery directly into the ischaemic limb. The aim of this study was to determine whether alginate encapsulation of therapeutic pro-angio/arteriogenic macrophages enhances their retention and ultimately improves limb perfusion. A reproducible GMP-compliant method for generating 300 µm alginate capsules was developed to encapsulate pro-angio/arteriogenic macrophages. Longitudinal analysis revealed no detrimental effect of encapsulation on cell number or viability in vitro, and macrophages retained their pro-angio/arteriogenic phenotype. Intramuscular delivery of encapsulated macrophages into the murine ischaemic hindlimb demonstrated increased cell retention compared with injection of naked cells (P = 0.0001), and that this was associated both enhanced angiogenesis (P = 0.02) and arteriogenesis (P = 0.03), and an overall improvement in limb perfusion (P = 0.0001). Alginate encapsulation of pro-angio/arteriogenic macrophages enhances cell retention and subsequent limb reperfusion in vivo. Encapsulation may therefore represent a means of improving the efficacy of cell-based therapies currently under investigation for the treatment of limb ischaemia.

Dissection of the host-pathogen interaction in human tuberculosis using a bioengineered 3-dimensional model.

Cell biology differs between traditional cell culture and 3-dimensional (3-D) systems, and is modulated by the extracellular matrix. Experimentation in 3-D presents challenges, especially with virulent pathogens. Mycobacterium tuberculosis (Mtb) kills more humans than any other infection and is characterised by a spatially organised immune response and extracellular matrix remodelling. We developed a 3-D system incorporating virulent mycobacteria, primary human blood mononuclear cells and collagen-alginate matrix to dissect the host-pathogen interaction. Infection in 3-D led to greater cellular survival and permitted longitudinal analysis over 21 days. Key features of human tuberculosis develop, and extracellular matrix integrity favours the host over the pathogen. We optimised multiparameter readouts to study emerging therapeutic interventions: cytokine supplementation, host-directed therapy and immunoaugmentation. Each intervention modulates the host-pathogen interaction, but has both beneficial and harmful effects. This methodology has wide applicability to investigate infectious, inflammatory and neoplastic diseases and develop novel drug regimes and vaccination approaches.

Thoughts on Scaffolds.

Scaffolds are instrumental in the engineering of functional tissues, and therefore have been an intense area of interest within regenerative biology and medicine in areas of research and development. Many approaches exist for creating scaffolds with either natural or synthetic advanced materials, which are subsequently coupled with cells and other materials and microintegrated with the aid of a bioreactor, finally forming a functional three-dimensional tissue. Although many advances have been made over the years, none of these have truly been successful, as postulated by literature for either biomedical or clinical utility. For example, generated reconstructs have many limitations, such as poor cell infiltration throughout the entire depth of the scaffold, the associated cost, and the time for generating functional reconstructs mimicking native tissue. These and other roadblocks have truly limited the use of scaffolds as tissue engineering biomaterials/building blocks in regenerative medicine. However, these obstacles have recently been overcome with new scaffolding technologies unearthed and pioneered in 2005, which demonstrate the ability to directly handle large quantities of multiple cell types with both a biopolymer and other advanced materials for simultaneously forming a three-dimensional living reconstruct mimicking native tissues. These recently discovered platform biotechnologies will have significant ramifications for the engineering of a three-dimensional tissue and for regenerative medicine in general, as these platforms are versatile.

Sustained Release of Cx43 Antisense Oligodeoxynucleotides from Coated Collagen Scaffolds Promotes Wound Healing.

Antisense oligodeoxynucleotides targeting the mRNA of the gap junction protein Cx43 promote tissue repair in a variety of different wounds. Delivery of the antisense drug has most often been achieved by a thermoreversible hydrogel, Pluronic F-127, which is very effective in the short term but does not allow for sustained delivery over several days. For chronic wounds that take a long time to heal, repeated dosing with the drug may be desirable but is not always compatible with conventional treatments such as the weekly changing of compression bandages on venous leg ulcers. Here the coating of collagen scaffolds with antisense oligonucleotides is investigated and a way to provide protection of the oligodeoxynucleotide drug is found in conjunction with sustained release over a 7 d period. This approach significantly reduces the normal foreign body reaction to the scaffold, which induces an increase of Cx43 protein and an inhibition of healing. As a result of the antisense integration into the scaffold, inflammation is reduced with the rate of wound healing and contracture is significantly improved. This coated scaffold approach may be very useful for treating venous leg ulcers and also for providing a sustained release of any other types of oligonucleotide drugs that are being developed.

Platform Technologies for Directly Reconstructing 3D Living Biomaterials.

Bio-electrospraying and cell electrospinning is explored for reconstructing living biomaterials for regenerative biology and medicine. The investigations carried out in this study demonstrate these approaches as platform biotechnologies for tissue reconstruction for repair, replacement, and rejuvenation of damaged and/or ageing tissues and/or organs.

The Extracellular Matrix Regulates Granuloma Necrosis in Tuberculosis.

A central tenet of tuberculosis pathogenesis is that caseous necrosis leads to extracellular matrix destruction and bacterial transmission. We reconsider the underlying mechanism of tuberculosis pathology and demonstrate that collagen destruction may be a critical initial event, causing caseous necrosis as opposed to resulting from it. In human tuberculosis granulomas, regions of extracellular matrix destruction map to areas of caseous necrosis. In mice, transgenic expression of human matrix metalloproteinase 1 causes caseous necrosis, the pathological hallmark of human tuberculosis. Collagen destruction is the principal pathological difference between humanised mice and wild-type mice with tuberculosis, whereas the release of proinflammatory cytokines does not differ, demonstrating that collagen breakdown may lead to cell death and caseation. To investigate this hypothesis, we developed a 3-dimensional cell culture model of tuberculosis granuloma formation, using bioelectrospray technology. Collagen improved survival of Mycobacterium tuberculosis-infected cells analyzed on the basis of a lactate dehydrogenase release assay, propidium iodide staining, and measurement of the total number of viable cells. Taken together, these findings suggest that collagen destruction is an initial event in tuberculosis immunopathology, leading to caseous necrosis and compromising the immune response, revealing a previously unappreciated role for the extracellular matrix in regulating the host-pathogen interaction.

Controlled Generation of Microspheres Incorporating Extracellular Matrix Fibrils for Three-Dimensional Cell Culture.

A growing body of evidence suggests that studying cell biology in classical two-dimensional formats, such as cell culture plasticware, results in misleading, non-physiological findings. For example, some aspects of cancer biology cannot be observed in 2D, but require 3D culture methods to recapitulate observations in vivo. Therefore, we developed a microsphere-based model to permit 3D cell culture incorporating physiological extracellular matrix components. Bio-electrospraying was chosen as it is the most advanced method to produce microspheres, with THP-1 cells as a model cell line. Bio-electrospraying parameters, such as nozzle size, polymer flow rate, and voltage, were systematically optimized to allow stable production of size controlled microspheres containing extracellular matrix material and human cells. We investigated the effect of bio-electrospraying parameters, alginate type and cell concentration on cell viability using trypan blue and propidium iodide staining. Bio-electrospraying had no effect on cell viability nor the ability of cells to proliferate. Cell viability was similarly minimally affected by encapsulation in all types of alginate tested (MVM, MVG, chemical- and food-grade). Cell density of 5 × 106 cells ml-1 within microspheres was the optimum for cell survival and proliferation. The stable generation of microspheres incorporating cells and extracellular matrix for use in a 3D cell culture will benefit study of many diverse diseases and permit investigation of cellular biology within a 3D matrix.

Cell electrospinning cardiac patches for tissue engineering the heart.

Cell electrospinning has tremendous applicability to a wide range of uses within both the laboratory and clinic. This has directly resulted from the technology's unique ability to immobilize multiple cell types with a wide range of molecules simultaneously within a fiber during the scaffold generation process. The technology has been shown to generate many cell laden complex architectures from true three-dimensional sheets to those multi-core vessels. Although those studies have demonstrated the versatility of this platform biotechnology, we show here for the first time the ability to immobilize primary cardiac myocytes within these fibers in our quest to develop this technology for creating three-dimensional cardiac patches which could be used for repairing, replacing and rejuvenating damaged, diseased and/or ageing cardiac tissues. These advances are unrivalled by any other technology currently available in the regenerative medicine toolbox, and have many interesting ramifications for repairing a damaged heart.

Cell electrospinning: an in vitro and in vivo study.

Cell electrospinning and aerodynamically assisted bio-threading are novel bioplatforms for directly forming large quantities of cell-laden scaffolds for creating living sheets and vessels in three-dimensions. The functional biological architectures generated will be useful in both the laboratory and the clinic.

Cardiac tissue engineering: renewing the arsenal for the battle against heart disease.

The development of therapies that lead to the regeneration or functional repair of compromised cardiac tissue is the most important challenge facing translational cardiovascular research today. During the last 25 years huge efforts have been made towards restoring the physiologic functions of the heart by means of delivering cell implants into the insulted heart, initially through 'naked cell' injections and more recently through the principle of cardiac tissue engineering and the use of elaborate delivery systems and priming mechanisms that include scaffolds, bioreactors or ex vivo manipulations of cells and support structures. In this review we summarise various approaches towards cardiac repair and highlight advances in the field of tissue engineering, ranging from a review of cell types used, to advances that attempt to address mechanistic and functional elements that are critical for successful restoration of the heart, including the maintenance of the extracellular matrix through scaffoldless cardiac sheets, strategies that promote neovascularisation and the precise micro-delivery of cell populations to form three-dimensional structures through bioengineering methods such as microfabrication.