Congenital aniridia is a panocular disorder that is typically characterized by iris hypoplasia and aniridia-associated keratopathy (AAK). AAK results in the progressive loss of corneal transparency and thereby loss of vision. Currently, there is no approved therapy to delay or prevent its progression, and clinical management is challenging because of phenotypic variability and high risk of complications after interventions; however, new insights into the molecular pathogenesis of AAK may help improve its management.
View Article and Find Full Text PDFPurpose: In our earlier study, we identified hsa-miR-150-5p as a highly expressed miRNA in enriched corneal epithelial stem cells (CESCs). In this study, we aimed to understand the molecular regulatory function of hsa-miR-150-5p in association with the maintenance of stemness in CESCs.
Methods: The target mRNAs of hsa-miR-150-5p were predicted and subjected to pathway analysis to identify targets for functional studies.
Our previous study demonstrated hsa-miR-143-3p as one of the highly expressed miRNAs in enriched corneal epithelial stem cells (CESCs). Hence this study aims to elucidate the regulatory role of hsa-miR-143-3p in the maintenance of stemness in CESCs. The target genes of hsa-miR-143-3p were predicted and subjected to pathway analysis to select the targets for functional studies.
View Article and Find Full Text PDFPurpose: To investigate if human oral mucosal fibroblasts (HOMF) from patients with limbal stem cell deficiency (LSCD) can be used as an autologous feeder layer to support the culture of epithelial cells for potential clinical use.
Methods: HOMF were isolated from oral mucosal biopsies obtained from the following groups of patients with LSCD: aniridia, mucous membrane pemphigoid (MMP), Stevens-Johnson syndrome (SJS), and ectodermal dysplasia (ED). The ability of these cells to support the culture of human limbal epithelial cells (HLE) was compared to that of HOMF from non-LSCD donors and 3T3s commonly used to culture epithelial cells for use in the clinic to treat LSCD.
Corneal endothelial cells (CECs) facilitate the function of maintaining the transparency of the cornea. Damage or dysfunction of CECs can lead to blindness, and the primary treatment is corneal transplantation. However, the shortage of cornea donors is a significant problem worldwide.
View Article and Find Full Text PDFThe integrity of innermost layer of the cornea, the corneal endothelium, is key to sustaining corneal transparency. Therefore, disease or injury causing loss or damage to the corneal endothelial cell population may threaten vision. Transplantation of corneal tissue is the standard treatment used to replace malfunctioning corneal endothelial cells.
View Article and Find Full Text PDFCultured limbal and oral epithelial cells have been successfully used to treat patients with limbal stem cell deficiency (LSCD). The most common culture method for these cell therapies utilizes amniotic membrane as a cell support and/or murine 3T3s as feeder fibroblasts. The aim of this study is to refine the production of autologous oral mucosal cell therapy for the treatment of LSCD.
View Article and Find Full Text PDFLimbal function is a key determinant of corneal epithelial integrity. Lineage tracing studies in mice have highlighted that the centripetal movement of epithelial progenitors from the limbus drives both the steady-state maintenance of the corneal epithelium and its regeneration following injury. It is well established that this is facilitated by a population of limbal epithelial stem cells within the limbus.
View Article and Find Full Text PDFLimbal epithelial stem cells are required for the maintenance and repair of the corneal epithelial surface. The difficulty in obtaining human corneal tissue for research purposes means that animal models for studying the corneal and limbal epithelium are extremely useful. Porcine corneal tissue represents an attractive experimental model, however, functional analysis of the limbal epithelial cell population is needed to validate the use of this tissue.
View Article and Find Full Text PDFWe report the repigmentation at the limbus in patients who underwent simple limbal epithelial transplant (SLET) for uniocular chemical injury. The first case is of an 8-year-old child who presented with grade 4 chemical injury, with limbal stem cell deficiency (LSCD) corresponding to 6 o' clock till 11 o' clock. He was managed by amniotic membrane graft in the acute stage and SLET after 6 months of the initial injury.
View Article and Find Full Text PDFThe objective of this study was to determine whether corneal stromal cells (CSCs) from the limbal and central corneal stroma in dogs have multipotent mesenchymal stem/stromal cell (MSC) properties, and whether this cell population can be differentiated into keratocyte-like cells (KDCs). Normal, donated, mesocephalic dog corneas were used to isolate CSC in vitro. Immunohistochemistry demonstrated a distinct population of CD90 expressing cells in the anterior stroma throughout the limbal and central cornea.
View Article and Find Full Text PDFAge-related macular degeneration (AMD) remains a major cause of blindness, with dysfunction and loss of retinal pigment epithelium (RPE) central to disease progression. We engineered an RPE patch comprising a fully differentiated, human embryonic stem cell (hESC)-derived RPE monolayer on a coated, synthetic basement membrane. We delivered the patch, using a purpose-designed microsurgical tool, into the subretinal space of one eye in each of two patients with severe exudative AMD.
View Article and Find Full Text PDFUnlabelled: The architecture of the human corneal stroma consists of a highly organized extracellular matrix (ECM) interspersed with keratocytes. Their progenitor cells; corneal stromal stem cells (CSSC) are located at the periphery, in the limbal stroma. A highly organized corneal ECM is critical for effective transmission of light but this structure may be compromised during injury or disease, resulting in loss of vision.
View Article and Find Full Text PDFMucous membrane pemphigoid (MMP) is a systemic mucosal scarring disease, commonly causing blindness, for which there is no antifibrotic therapy. Aldehyde dehydrogenase family 1 (ALDH1) is upregulated in both ocular MMP (OMMP) conjunctiva and cultured fibroblasts. Application of the ALDH metabolite, retinoic acid (RA), to normal human conjunctival fibroblasts in vitro induced a diseased phenotype.
View Article and Find Full Text PDFAim: To investigate human oral mucosal fibroblasts (HOMF) and human limbal fibroblasts (HLF) as alternatives to murine 3T3 feeder fibroblasts currently used to support epithelial cell expansion for the treatment of limbal epithelial stem cell deficiency.
Methods: HLF and HOMF were compared with 3T3s for their ability to support the culture of human limbal epithelial cells and human oral mucosal epithelial cells.
Results: HOMF, but not HLF, were equivalent to 3T3s in terms of the number of epithelial population doublings achieved.
Epithelial stem cells of the ocular surface are essential for the maintenance of corneal transparency and therefore for vision. Human corneal/limbal epithelial stem cells (LESCs) are believed to reside in the limbus, the interface between the peripheral cornea and neighboring conjunctiva. A specific anatomical microenvironment called the niche regulates the proliferative and differentiation potential of LESCs and their daughter cells.
View Article and Find Full Text PDFIn the past decade, stem cell therapy has been increasingly employed for the treatment of various diseases. Subsequently, there has been a great interest in the manufacture of stem cells under good manufacturing practice, which is required by law for their use in humans. The cells for sight Stem Cell Therapy Research Unit, based at UCL Institute of Ophthalmology, delivers somatic cell-based and tissue-engineered therapies to patients suffering from blinding eye diseases at Moorfields Eye Hospital (London, UK).
View Article and Find Full Text PDFCongenital hereditary endothelial dystrophy 1 (CHED1) and posterior polymorphous corneal dystrophy 1 (PPCD1) are autosomal-dominant corneal endothelial dystrophies that have been genetically mapped to overlapping loci on the short arm of chromosome 20. We combined genetic and genomic approaches to identify the cause of disease in extensive pedigrees comprising over 100 affected individuals. After exclusion of pathogenic coding, splice-site, and copy-number variations, a parallel approach using targeted and whole-genome sequencing facilitated the identification of pathogenic variants in a conserved region of the OVOL2 proximal promoter sequence in the index families (c.
View Article and Find Full Text PDFPurpose: Creation of an in vitro model incorporating specific features that characterize a particular stem niche would allow researchers to study stem cell behavior in a more physiological environment.
Materials And Methods: We have developed a tissue engineering process (RAFT) that rapidly and reliably creates bioengineered limbal crypts (BLCs) in the surface of collagen-based tissue equivalents (TEs). These BLCs mimic the three-dimensional topography of the limbal crypts (LCs), located in the limbal region of the human cornea, which are home to a population of limbal epithelial stem cells (LESCs).
The transplantation of limbal epithelial stem cells (LESCs) cultured in vitro is a great advance in the treatment of patients suffering from LESC deficiency. However, the optimal technique for LESC isolation from a healthy limbal niche has not yet been established. Our aim was to determine which isolation method renders the highest recovery of functional LESCs from the human limbus.
View Article and Find Full Text PDFHuman limbal epithelial cells (HLE) and corneal stromal stem cells (CSSC) reside in close proximity in vivo in the corneal limbal stem cell niche. However, HLE are typically cultured in vitro without supporting niche cells. Here, we re-create the cell-cell juxtaposition of the native environment in vitro, to provide a tool for investigation of epithelial-stromal cell interactions and to optimize HLE culture conditions for potential therapeutic application.
View Article and Find Full Text PDFExperimental animals have been used extensively in the goal of developing sight-saving therapies for humans. One example is the development of transplantation of cultured limbal epithelial stem cells (LESC) to restore vision following ocular surface injury or disease. With clinical trials of cultured LESC therapy underway in humans and a potential companion animal population suffering from similar diseases, it is perhaps time to give something back.
View Article and Find Full Text PDFHuman limbal epithelial stem cells (LESCs) are essential for the maintenance of the corneal epithelium of the ocular surface. LESCs are located within limbal crypts between the palisades of Vogt in the limbus; the interface between the peripheral cornea and conjunctiva. The limbal crypts have been proposed as a LESC niche owing to their support of epithelial cells, which can form holoclone colonies in vitro.
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