Development of Biomimetic Substrates for Limbal Epithelial Stem Cells Using Collagen-Based Films, Hyaluronic Acid, Immortalized Cells, and Macromolecular Crowding.

Despite the promising potential of cell-based therapies developed using tissue engineering techniques to treat a wide range of diseases, including limbal stem cell deficiency (LSCD), which leads to corneal blindness, their commercialization remains constrained. This is primarily attributable to the limited cell sources, the use of non-standardizable, unscalable, and unsustainable techniques, and the extended manufacturing processes required to produce transplantable tissue-like surrogates. Herein, we present the first demonstration of the potential of a novel approach combining collagen films (CF), hyaluronic acid (HA), human telomerase-immortalized limbal epithelial stem cells (T-LESCs), and macromolecular crowding (MMC) to develop innovative biomimetic substrates for limbal epithelial stem cells (LESCs).

Macromolecular crowding agent dependent extracellular matrix deposition and growth factor retention in human corneal fibroblast cultures.

The major obstacle in the commercialisation and clinical translation of tissue engineered medicines is the required for the development of implantable tissue surrogates prolonged in vitro culture. Macromolecular crowding (MMC) enhances and accelerates extracellular matrix (ECM) deposition, thus offering an opportunity to bridge the gap between research and development in tissue engineered substitutes. However, the optimal MMC agent is still elusive.

Clinically correlated dose of the amniotic membrane extract is superior to its transplantation in corneal wound healing.

Purpose: This study investigates the superiority of sterile lyophilized amniotic membrane extract (AME) prepared at a clinically correlated dose over amniotic membrane transplantation (AMT) in an experimental corneal wound model.

Methods: AME was prepared from a pool of five amniotic membranes. After homogenizing the membranes, they were lyophilized and sterilized by gamma radiation to obtain sterile, lyophilized AME powder.

Gums as Macromolecular Crowding Agents in Human Skin Fibroblast Cultures.

Even though tissue-engineered medicines are under intense academic, clinical, and commercial investigation, only a handful of products have been commercialised, primarily due to the costs associated with their prolonged manufacturing. While macromolecular crowding has been shown to enhance and accelerate extracellular matrix deposition in eukaryotic cell culture, possibly offering a solution in this procrastinating tissue-engineered medicine development, there is still no widely accepted macromolecular crowding agent. With these in mind, we herein assessed the potential of gum Arabic, gum gellan, gum karaya, and gum xanthan as macromolecular crowding agents in WS1 skin fibroblast cultures (no macromolecular crowding and carrageenan were used as a control).

Corneal fibrosis: From in vitro models to current and upcoming drug and gene medicines.

Fibrotic diseases are characterised by myofibroblast differentiation, uncontrolled pathological extracellular matrix accumulation, tissue contraction, scar formation and, ultimately tissue / organ dysfunction. The cornea, the transparent tissue located on the anterior chamber of the eye, is extremely susceptible to fibrotic diseases, which cause loss of corneal transparency and are often associated with blindness. Although topical corticosteroids and antimetabolites are extensively used in the management of corneal fibrosis, they are associated with glaucoma, cataract formation, corneoscleral melting and infection, imposing the need of far more effective therapies.

An important detail that is still not clear in amniotic membrane applications: How do we store the amniotic membrane best?

The use of fresh amniotic membrane (AM) is not a viable option, as it has many disadvantages. Preserving the AM reduces the risk of cross-infection and maintains its effectiveness for a long time. In order to maximize the therapeutic effects of the AM, the basic need is to preserve its vitality and the bioactive molecules it contains.

Perceptions of plain packaging and health warnings among university students in Turkey: a survey-based experiment.

Background: Cigarette pack design plays a crucial role in attracting customers, especially when other marketing methods are limited by policy. University students who engage in casual smoking take the risk of developing an addiction. The objective of this study was to assess the effects of plain packaging (PP) and graphic health warnings (GHWs) on cigarette packages on three outcome variables (negative affect, avoidant responses, and intentions to quit) among ever-smoker university students in Ankara, Turkey, where youth smoking prevalence is high.

Macromolecular crowding in the development of a three-dimensional organotypic human breast cancer model.

Although cell-derived matrices are at the forefront of scientific research and technological innovation for the development of in vitro tumour models, their two-dimensional structure and low extracellular matrix composition restrict their capacity to accurately predict toxicity of candidate molecules. Herein, we assessed the potential of macromolecular crowding (a biophysical phenomenon that significantly enhances and accelerates extracellular matrix deposition, resulting in three-dimensional tissue surrogates) in improving cell-derived matrices in vitro tumour models. Among the various decellularisation protocols assessed (NHOH, DOC, SDS/EDTA, NP40), the NP40 appeared to be the most effective in removing cellular matter and the least destructive to the deposited matrix.

Evaluation of Limbal Stem Cell Transplant Success in Ocular Chemical Injury.

Objectives: We evaluated limbal stem cell transplant success in limbal stem cell deficiency due to chemical injury at a tertiary eye care center in Turkey with a novel system for describing limbal stem cell deficiency, as developed by the Limbal Stem Cell Working Group.

Materials And Methods: Medical records of 80 eyes of 80 patients after limbal stem cell transplant for limbal stem cell deficiency secondary to chemical injury were included, with patients grouped according to surgical procedure, ie, limbal autograft, limbal allograft, and cultivated limbal epithelial cell transplant. Surgical success was defined as improvement in postoperative year 1 of limbal stem cell deficiency stage.

Multi-parametric evaluation of autologous cultivated Limbal epithelial cell transplantation outcomes of Limbal stem cell deficiency due to chemical burn.

Background: The sparsity of established tools for the grading of limbal stem cell deficiency hinder objective assessments of the clinical outcome of cultivated limbal epithelial cell transplantation. To advance towards the development of standards for the comparison of the outcomes of these bio-surgical protocols we have now applied a battery of recognized objective and patient-declared subjective outcome criteria to the autologous modality of cultivated limbal epithelial cell transplantation.

Methods: The prospective study involved ten patients (M/F = 9/1; mean age = 42.

Formation of Corneal Stromal-Like Assemblies Using Human Corneal Fibroblasts and Macromolecular Crowding.

Tissue engineering by self-assembly allows for the formation of living tissue substitutes, using the cells' innate capability to produce and deposit tissue-specific extracellular matrix. However, in order to develop extracellular matrix-rich implantable devices, prolonged culture time is required in traditionally utilized dilute ex vivo microenvironments. Macromolecular crowding, by imitating the in vivo tissue density, dramatically accelerates biological processes, resulting in enhanced and accelerated extracellular matrix deposition.

The role of PRP and adipose tissue-derived keratinocytes on burn wound healing in diabetic rats.

Diabetic burn wounds and ulcers are significant complications of diabetic patients. The aim of this study is to investigate the use of platelet rich-plasma (PRP) and/or keratinocyte-like cells (KLCs) in diabetic thermal wound rat model and to evaluate EGF, FGF-2, TGF-β1, COL1α2, MCP-1 and VEGF-α as wound healing markers at gene expression level. In this study, we used adipose tissue as the source of mesenchymal stem cells (MSCs) and differentiated MSCs into KLCs.

Uniqueness Properties of The Solution of The Inverse Problem for The Sturm-Liouville Equation With Discontinuous Leading Coefficient.

The present paper studies uniqueness properties of the solution of the inverse problem for the Sturm-Liouville equation with discontinuous leading coefficient and the separated boundary conditions. It is proved that the considered boundary-value is uniquely reconstructed, i.e.

Comparison of culture media indicates a role for autologous serum in enhancing phenotypic preservation of rabbit limbal stem cells in explant culture.

In this study, we aimed to compare the effects of six different cell culture media and autologous serum (AS) on the phenotypic characteristics of rabbit limbal epithelial stem cells (LESC) cultivated on porous polyethylene terephthalate (PET) membranes. Limbal explants from rabbit corneas were grown on PET membrane inserts in five different media: DMEM-F12 with fetal bovine serum (FBS) (DMEM-F12-FBS), with pluripotin (DMEM-F12-pluripotin) and with autologous serum (DMEM-F12-AS), Epilife, Keratinocyte Serum Free Medium (KSFM) and Defined-Keratinocyte Serum Free Medium. The effects of different media were evaluated by total cell yield from explants, measuring the expression of proteins by immunofluorescence and gene expression by Real Time PCR.

Limbal Stem Cell Deficiency and Treatment with Stem Cell Transplantation.

The cornea is the outermost tissue of the eye and it must be transparent for the maintenance of good visual function. The superficial epithelium of the cornea, which is renewed continuously by corneal stem cells, plays a critical role in the permanence of this transparency. These stem cells are localized at the cornea-conjunctival transition zone, referred to as the limbus.

Corneal recovery in a rabbit limbal stem cell deficiency model by autologous grafts of tertiary outgrowths from cultivated limbal biopsy explants.

Purpose: To determine the corneal regenerative capacity of sequentially generated primary, secondary, and tertiary limbal explant outgrowths in a limbal stem cell deficiency (LSCD) surgical model.

Methods: Two-millimeter-long limbal shallow biopsies were surgically excised from the upper quadrant of the right eye of rabbits and set on preserved amniotic membrane for explant culture. After the generation of primary outgrowth, the biopsies were sequentially transferred to new amniotic membrane to generate secondary and then tertiary outgrowths.