Storable Cell-Laden Alginate Based Bioinks for 3D Biofabrication.

Over the last decade, progress in three dimensional (3D) bioprinting has advanced considerably. The ability to fabricate complex 3D structures containing live cells for drug discovery and tissue engineering has huge potential. To realise successful clinical translation, biologistics need to be considered.

Alginate in corneal tissue engineering.

Corneal blindness is the major cause of vision impairment and the fourth-largest leading cause of blindness worldwide. An allograft corneal transplant is the most routine treatment for visual loss. Further complications can occur, such as transplant rejection, astigmatism, glaucoma, uveitis, retinal detachment, corneal ulceration due to reopening of the surgical wounds, and infection.

Use of biomaterials in corneal endothelial repair.

Human corneal endothelium (HCE) is a single layer of hexagonal cells that lines the posterior surface of the cornea. It forms the barrier that separates the aqueous humor from the rest of the corneal layers (stroma and epithelium layer). This layer plays a fundamental role in maintaining the hydration and transparency of the cornea, which in turn ensures a clear vision.

Milliscale Substrate Curvature Promotes Myoblast Self-Organization and Differentiation.

Biological tissues comprise complex structural environments known to influence cell behavior via multiple interdependent sensing and transduction mechanisms. Yet, and despite the predominantly nonplanar geometry of these environments, the impact of tissue-size (milliscale) curvature on cell behavior is largely overlooked or underestimated. This study explores how concave, hemicylinder-shaped surfaces 3-50 mm in diameter affect the migration, proliferation, orientation, and differentiation of C2C12 myoblasts.

Effect of isolation method on human corneal stromal cell behaviour.

Current research on healthy corneal stromal cells will typically use primary cells as they are the most representative of in vivo behaviour. Primary cells are normally isolated from the limbus of discarded donor peripheral corneal tissue left over from transplantation (due to its relative abundance). Therefore, the central part of the cornea is less used in research as this tissue is usually used for transplantation.

Response of human oral mucosal epithelial cells to different storage temperatures: A structural and transcriptional study.

Purpose: Seeking to improve the access to regenerative medicine, this study investigated the structural and transcriptional effects of storage temperature on human oral mucosal epithelial cells (OMECs).

Methods: Cells were stored at four different temperatures (4°C, 12°C, 24°C and 37°C) for two weeks. Then, the morphology, cell viability and differential gene expression were examined using light and scanning electron microscopy, trypan blue exclusion test and TaqMan gene expression array cards, respectively.

Scale-Up Technologies for the Manufacture of Adherent Cells.

Great importance is being given to the impact our food supply chain and consumers' food habits are having on the environment, human health, and animal welfare. One of the latest developments aiming at positively changing the food ecosystem is represented by cultured meat. This form of cellular agriculture has the objective to generate slaughter-free meat products starting from the cultivation of few cells harvested from the animal tissue of interest.

Biomechanical Modulation Therapy-A Stem Cell Therapy Without Stem Cells for the Treatment of Severe Ocular Burns.

Ocular injuries caused by chemical and thermal burns are often unmanageable and frequently result in disfigurement, corneal haze/opacification, and vision loss. Currently, a considerable number of surgical and pharmacological approaches are available to treat such injuries at either an acute or a chronic stage. However, these existing interventions are mainly directed at (and limited to) suppressing corneal inflammation and neovascularization while promoting re-epithelialization.

Hypothermically Stored Adipose-Derived Mesenchymal Stromal Cell Alginate Bandages Facilitate Use of Paracrine Molecules for Corneal Wound Healing.

Adipose-derived mesenchymal stromal cells (Ad-MSCs) may alleviate corneal injury through the secretion of therapeutic factors delivered at the injury site. We aimed to investigate the therapeutic factors secreted from hypothermically stored, alginate-encapsulated Ad-MSCs' bandages in in vitro and in vivo corneal wounds. Ad-MSCs were encapsulated in 1.

Encapsulation of human limbus-derived stromal/mesenchymal stem cells for biological preservation and transportation in extreme Indian conditions for clinical use.

Human limbus-derived stromal/mesenchymal stem cells (hLMSC) can be one of the alternatives for the treatment of corneal scars. However, reliable methods of storing and transporting hLMSC remains a serious translational bottleneck. This study aimed to address these limitations by encapsulating hLMSC in alginate beads.

YAP, ΔNp63, and β-Catenin Signaling Pathways Are Involved in the Modulation of Corneal Epithelial Stem Cell Phenotype Induced by Substrate Stiffness.

Recent studies have established that the phenotype of epithelial stem cells residing in the corneal periphery (the limbus) depends on this niche's distinct biomechanical properties. However, the signaling pathways underlying this dependency are still poorly understood. To address this issue, we investigated the effect of substrate stiffness on the migration, proliferation, and molecular phenotype of human limbal epithelial stem cells (LESCs).

Mesenchymal stromal cells for ocular surface repair.

Introduction: Cornea is a transparent, robust tissue that comprises highly organized cells. Disruption of this specialized tissue can lead to scarring and subsequent blindness, making corneal damage a considerable challenge worldwide. At present, the available medical treatments are unable to address the wide range of corneal diseases.

Assessment of corneal substrate biomechanics and its effect on epithelial stem cell maintenance and differentiation.

Whilst demonstrated extensively in vitro, the control of cell behaviour via modulation of substrate compliance in live tissues has not been accomplished to date. Here we propose that stem cells can be regulated solely through in situ modulation of tissue biomechanics. By first establishing, via high-resolution Brillouin spectro-microscopy, that the outer edge (limbus) of live human corneas has a substantially lower bulk modulus compared to their centre, we then demonstrate that this difference is associated with limbal epithelial stem cell (LESC) residence and YAP-dependent mechanotransduction.

Autogenous Biofabrication of Nativelike, Scaffold-Free Human Skin Equivalents Using a Smart, Enzyme-Degradable Tissue Templating Coating.

In this study, we used tissue templating technology to direct human dermal fibroblasts to biofabricate large-area tissues that closely emulate the natural dermis. This technology also allowed the new tissues to promote their own release from the template surface, thus facilitating their recovery as self-sustained, scaffold-free dermal equivalents solely comprising human cells and their own extracellular matrix. The structure and composition of these dermal self-lifting autogenous tissue equivalents (SLATEs) were evaluated in detail and were shown to closely correlate to normal tissue function.

Keratoconus at a Molecular Level: A Review.

Keratoconus is the most common ectatic disease of the cornea. The disease is usually detected between ages 15 and 25. Incidence is estimated at one out of every 2000 individuals, with some specific ethnic groups being more at risk.

Alginate encapsulated multipotent adult progenitor cells promote corneal stromal cell activation via release of soluble factors.

To reduce the increasing need for corneal transplantation, attempts are currently aiming to restore corneal clarity, one potent source of cells are multipotent adult progenitor cells (MAPC®). These cells release a powerful cocktail of paracrine factors that can guide wound healing and tissue regeneration. However, their role in corneal regeneration has been overlooked.

3D bioprinting of a corneal stroma equivalent.

Corneal transplantation constitutes one of the leading treatments for severe cases of loss of corneal function. Due to its limitations, a concerted effort has been made by tissue engineers to produce functional, synthetic corneal prostheses as an alternative recourse. However, successful translation of these therapies into the clinic has not yet been accomplished.

Template Curvature Influences Cell Alignment to Create Improved Human Corneal Tissue Equivalents.

To accurately create corneal stromal equivalents with native-like structure and composition, a new biofunctionalized, curved template is developed that allows the precise orientation of cells and of their extracellular matrix. This template is the first demonstration that curvature alone is sufficient to induce the alignment of human corneal stromal cells, which in turn are able to biofabricate stromal tissue equivalents with cornea-like shape and composition. Specifically, tissues self-released from curved templates show a highly organized nanostructure, comprised of aligned collagen fibrils, significantly higher expression of corneal stroma-characteristic markers keratocan, lumican, decorin, ALDH3, and CHST6 (p = 0.

Developing a Continuous Bioprocessing Approach to Stromal Cell Manufacture.

To this day, the concept of continuous bioprocessing has been applied mostly to the manufacture of molecular biologics such as proteins, growth factors, and secondary metabolites with biopharmaceutical uses. The present work now sets to explore the potential application of continuous bioprocess methods to source large numbers of human adherent cells with potential therapeutic value. To this purpose, we developed a smart multifunctional surface coating capable of controlling the attachment, proliferation, and subsequent self-detachment of human corneal stromal cells.

Preservation and stability of cell therapy products: recommendations from an expert workshop.

If the field of regenerative medicine is to deliver therapies, rapid expansion and delivery over considerable distances to large numbers of patients is needed. This will demand efficient stabilization and shipment of cell products. However, cryopreservation science is poorly understood by life-scientists in general and in recent decades only limited progress has been made in the technology of preservation and storage of cells.

Controlling the 3D architecture of Self-Lifting Auto-generated Tissue Equivalents (SLATEs) for optimized corneal graft composition and stability.

Ideally, biomaterials designed to play specific physical and physiological roles in vivo should comprise components and microarchitectures analogous to those of the native tissues they intend to replace. For that, implantable biomaterials need to be carefully designed to have the correct structural and compositional properties, which consequently impart their bio-function. In this study, we showed that the control of such properties can be defined from the bottom-up, using smart surface templates to modulate the structure, composition, and bio-mechanics of human transplantable tissues.

Assessing corneal biomechanics with Brillouin spectro-microscopy.

A new Brillouin spectro-microscope was designed and built to investigate the mechanical properties of bovine and human corneas. This instrument integrates a single-stage virtually imaged phased array spectrometer with a novel adaptive-optics interferometric filter to achieve unprecedented rejection of the elastic background signal. As a result, highly-resolved, reproducible data from both thin and thick collagen-based materials were obtained.

Alginate-Encapsulation for the Improved Hypothermic Preservation of Human Adipose-Derived Stem Cells.

Despite considerable progress within the cell therapy industry, unmet bioprocessing and logistical challenges associated with the storage and distribution of cells between sites of manufacture and the clinic exist. We examined whether hypothermic (4°C-23°C) preservation of human adipose-derived stem cells could be improved through their encapsulation in 1.2% calcium alginate.

Supra-molecular assembly of a lumican-derived peptide amphiphile enhances its collagen-stimulating activity.

C16-YEALRVANEVTLN, a peptide amphiphile (PA) incorporating a biologically active amino acid sequence found in lumican, has been examined for its influence upon collagen synthesis by human corneal fibroblasts in vitro, and the roles of supra-molecular assembly and activin receptor-like kinase ALK receptor signaling in this effect were assessed. Cell viability was monitored using the Alamar blue assay, and collagen synthesis was assessed using Sirius red. The role of ALK signaling was studied by receptor inhibition.