Search Results (122)

Corneal transplantation is often considered the last resort for severe corneal epithelial disorders, especially limbal stem cell deficiency (LSCD). Tissue engineering offers novel strategies to mitigate the shortage of corneal transplant donors. However, low cell viability and compromised functionality in tissue engineering represent a major challenge. In this review, we describe the key characteristics required for corneal epithelium bioscaffolds. We summarize the research progress centered on optimizing cell activity and functionality in the past 10 years from four key perspectives: the sourcing of cells, seed cell pretreatments, biomaterial optimization, and engineered culture system innovation. The sources, isolation, and induction methods of seed cells are described, and the advantages and disadvantages of existing clinical treatment methods are compared. Furthermore, we compare existing clinical therapies and summarize promising seed cell pretreatment strategies for the first time. Several innovative engineered cell culture systems are exhibited as well. We demonstrated how to preserve cell viability through bioscaffold stiffness modulation, topographic design, and application of innovative fabrication techniques. Finally, we propose a personalized and precise regeneration strategy based on high-resolution images, digital modeling, bioprinting, and machine learning. Full article

Cell-based therapeutics are redefining interventions for vision loss by enabling tissue replacement, regeneration, and neuroprotection. This review surveys contemporary cellular strategies in ophthalmology through the lenses of therapeutic effectiveness, translational readiness, and governance. We profile principal sources—embryonic and induced pluripotent stem cells, mesenchymal stromal cells, retinal pigment epithelium, retinal progenitor and limbal stem cells—and enabling platforms including extracellular vesicles, encapsulated cell technology and biomaterial scaffolds. We synthesize clinical evidence across age-related macular degeneration, inherited retinal dystrophies, and corneal injury/limbal stem-cell deficiency, and highlight emerging applications for glaucoma and diabetic retinopathy. Delivery routes (subretinal, intravitreal, anterior segment) and graft formats (single cells, sheets/patches, organoids) are compared using standardized structural and functional endpoints. Persistent barriers include GMP-compliant derivation and release testing; differentiation fidelity, maturation, and potency; genomic stability and tumorigenicity risk; graft survival, synaptic integration, and immune rejection despite ocular immune privilege; the scarcity of validated biomarkers and harmonized outcome measures and ethical, regulatory, and health-economic constraints. Promising trajectories span off-the-shelf allogeneic products, patient-specific iPSC-derived grafts, organoid and 3D-bioprinted tissues, gene-plus-cell combinations, and cell-free extracellular-vesicle therapeutics. Overall, cell-based therapies remain investigational. With adequately powered trials, methodological harmonization, long-term surveillance, scalable xeno-free manufacturing, and equitable access frameworks, they may eventually become standards of care; at present, approvals are limited to specific products/indications and regions, and no cell therapy is the standard of care for retinal disease. Full article

Background: Antibody-drug conjugates (ADCs) have ushered in a new era of precision oncology by combining the targeting specificity of monoclonal antibodies with the potent cytotoxicity of chemotherapeutic drugs. However, the cellular and molecular mechanisms underlying their dose-limiting ocular toxicity remain unclear. Elahere™, the first FDA-approved ADC targeting folate receptor α (FRα), demonstrates remarkable efficacy in platinum-resistant ovarian cancer but causes keratitis and other ocular toxicities in some patients. Notably, FRα is not expressed in the corneal epithelium—the primary site of damage—highlighting the urgent need to elucidate its underlying mechanisms. The aim of this study was to identify the cell-type-specific molecular mechanisms underlying Elahere-induced ocular toxicity. Methods: Sprague-Dawley rats were treated with intravenous Elahere (20 mg/kg) or vehicle weekly for five weeks. Ocular toxicity was determined by clinical examination and histopathology. Corneal single-cell suspensions were analyzed using the BD Rhapsody single-cell RNA sequencing (scRNA-seq) platform. Bioinformatic analyses to characterize changes in corneal cell populations, gene expression, and signaling pathways included cell clustering, differential gene expression, pseudotime trajectory inference, and cell-cell interaction modeling. Results: scRNA-seq profiling of 47,606 corneal cells revealed significant damage to the ocular surface and corneal epithelia in the Elahere group. Twenty distinct cell types were identified. Elahere depleted myeloid immune cells; in particular, homeostatic gene expression was suppressed in phagocytic macrophages. Progenitor populations (limbal stem cells and basal cells) accumulated (e.g., a ~2.6-fold expansion of limbal stem cells), while terminally differentiated cells decreased in corneal epithelium, indicating differentiation blockade. Endothelial cells exhibited signs of injury and inflammation, including reduced angiogenic subtypes and heightened stress responses. Folate receptor alpha, the target of Elahere, was expressed in endothelial and stromal cells, potentially driving stromal cells toward a pro-fibrotic phenotype. Fc receptor genes were predominantly expressed in myeloid cells, suggesting a potential mechanism underlying their depletion. Conclusions: Elahere induces complex, multi-compartmental ocular toxicity characterized by initial perturbations in vascular endothelial and immune cell populations followed by the arrest of epithelial differentiation and stromal remodeling. These findings reveal a cascade of cellular disruptions and provide mechanistic insights into mitigating Elahere-associated ocular side effects. Full article

Limbal dermoids are congenital, benign, choristomatous growths affecting the corneal-limbal junction. Conventional excision techniques often result in persistent epithelial defects, corneal thinning, and vascularization due to sectoral limbal stem cell deficiency. This study investigated a novel surgical approach for limbal dermoid excision, utilizing Bowman’s membrane lenticule and autologous limbal stem cell transplantation, aimed at improving epithelial healing and visual outcomes. Thirty-four subjects (24 females, 10 males; mean age 8.33 ± 6.47 years) with limbal dermoids underwent the procedure. After dermoid excision, a Bowman’s membrane lenticule was placed over the defect and tucked 1 mm beneath the surrounding tissue. Sectoral limbal reconstruction was then performed using the AutoSLET technique. Pre- and postoperative assessments included visual acuity, corneal thickness, and epithelialization time. Statistical analysis employed paired t-tests. The mean epithelialization time was 3.36 ± 0.74 weeks, indicating rapid healing. Best-corrected visual acuity (BCVA) significantly improved from a preoperative mean of 0.136 ± 0.121 decimal units to a postoperative mean of 0.336 ± 0.214 decimal units (p < 0.001). Corneal thickness also demonstrated a significant increase, rising from a preoperative mean of 294 ± 49.68 microns to a postoperative mean of 484 ± 5.037 microns (p < 0.001). There is a transient edema below the Bowman lenticule observed in many cases, which resolves with deposition of granulation tissue. The findings suggest that the combined use of Bowman’s membrane lenticule and autologous limbal stem cell transplantation offers a promising surgical strategy for limbal dermoid excision. This technique promotes rapid epithelialization and leads to significant improvements in visual acuity and corneal thickness compared to conventional methods. The utilization of Bowman’s membrane as a natural basement membrane and the direct application of limbal stem cells facilitate enhanced epithelial healing and visual rehabilitation. While the study is limited by its small sample size, the results demonstrate the potential of this novel approach in managing limbal dermoids effectively. Full article

Background/Objectives: Rho-associated coiled-coil-containing protein kinase inhibitors (ROCKis) have now become known as modulators of corneal endothelial wound repair and cell survival. However, evidence remains fragmented across laboratory and clinical reports. We performed a systematic review to synthesize preclinical and clinical data on ROCKis in corneal disease, assess their efficacy and safety, and identify research gaps. Methods: We searched PubMed, Web of Science, Scopus, and Google Scholar (until May 2025) for English-language original studies evaluating ROCKis in corneal models or patients. Inclusion criteria encompassed in vitro, ex vivo, in vivo, and clinical trials reporting functional outcomes (endothelial cell density, wound closure, visual acuity). Results: Thirty-one studies met criteria: 14 preclinical studies and 17 clinical studies. Preclinical models (rabbit, porcine, human explants) uniformly showed ROCKis (Y-27632, Ripasudil, Netarsudil, H-1152) accelerate corneal endothelial cell proliferation, migration, and restoration of a hexagonal monolayer with improved barrier and pump function over days to weeks. In 17 clinical investigations, topical Ripasudil or Netarsudil and cultured cell injections achieved significant corneal thinning, endothelial cell density and central corneal thickness changes, and visual acuity improvements (≥2 lines) with minimal adverse events. Overall bias was moderate in non-randomized studies and low in the RCTs. Conclusions: ROCKis demonstrate consistent pro-regenerative effects on corneal endothelium in multiple models and show promising clinical efficacy in Fuchs endothelial dystrophy and pseudophakic endothelial failure. Future work should explore novel delivery systems and larger controlled trials to optimize dosing, safety, and long-term outcomes. Full article

Bilateral limbal stem cell deficiency (LSCD) can be effectively treated with cultivated oral mucosa epithelial cell transplantation (COMET). However, COMET is associated with greater superficial neovascularization than limbal stem cell (LESC) transplantation, the gold standard for unilateral LSCD. To investigate the intrinsic molecular features of cells intended for grafting, we assessed the in vitro expression of genes involved in vascularization and inflammation using real-time quantitative PCR and multifactorial linear models. Oral mucosal epithelial cells (OMECs) and limbal epithelial cells (LECs) were cultured in either conventional (COM) or xenobiotic-free (XF) media on fibrin substrates. Gene expression profiling revealed distinct transcriptional signatures. The pro-angiogenic genes AGR2, ANGPTL2, CRYAB, EREG, JAM3, and S100A4 were significantly higher in LECs (adjusted p < 0.01), whereas FGF2 was higher in OMECs (adjusted p < 0.001). The anti-angiogenic genes TIMP3 and SERPINF1 were higher in LECs (adjusted p < 0.01), while COL18A1 was higher in OMECs (adjusted p < 0.01). OMECs also showed significantly greater expression of the immunoregulatory genes IL1B, IL6, TNF, CXCL10, and IL1RN (adjusted p < 0.01). Cultivation induced phenotypic changes in OMECs, with COM and XF media exerting comparable effects. These results highlight the contribution of inflammatory mediators to neovascularization following COMET. Full article

Background/Objectives: The management of ocular tumors often necessitates surgery, either alone or in combination with radiotherapy, chemotherapy, or other modalities. While crucial for tumor control, these treatments can significantly impact the ocular surface, leading to both acute and chronic complications. This review examines iatrogenic ocular surface diseases resulting from oncologic interventions, emphasizing their pathophysiology, diagnostic challenges, and management strategies. Methods: A literature review was conducted to identify studies on iatrogenic ocular surface complications associated with ocular tumor treatments. Results: Ocular surface complications include direct damage from surgical manipulation, leading to corneal opacities and persistent epithelial defects, as well as dry eye disease secondary to postoperative chemosis. These disruptions may progress to more severe conditions such as keratopathy, corneal ulcers, limbal stem cell deficiency, and stromal scarring, further impairing visual function. Structural alterations contribute to eyelid malpositions—including ectropion, entropion, round eye, and lagophthalmos—which exacerbate exposure-related damage and ocular surface instability. In cases of uveal melanomas, the exposure of episcleral brachytherapy plaques can induce chronic conjunctival irritation, promoting adhesion formation and symblepharon. Surgical interventions disrupt ocular surface homeostasis, while radiotherapy and chemotherapy exacerbate these effects through cytotoxic and inflammatory mechanisms. Conclusions: Preventing and managing iatrogenic ocular surface complications require a multidisciplinary approach involving early diagnosis, personalized treatment strategies, and targeted postoperative care. Comprehensive pre- and postoperative planning is essential to optimize both visual function and long-term ocular surface integrity, ultimately ensuring a balance between oncologic control with functional and aesthetic preservation. Full article

Persistent corneal epithelial defects (PCEDs) are a challenging ocular condition characterized by the failure of complete corneal epithelial healing after an insult or injury, even after 14 days of standard care. There is a lack of therapeutics that target this condition and encourage re-epithelialization of the corneal surface in a timely and efficient manner. This review aims to provide an overview of current standards of management for PCEDs, highlighting novel, emerging treatments in this field. While many of the current non-surgical treatments aim to provide lubrication and mechanical support, novel non-surgical approaches are undergoing development to harness the proliferative and healing properties of human mesenchymal stem cells, platelets, lufepirsen, hyaluronic acid, thymosin ß4, p-derived peptide, and insulin-like growth factor for the treatment of PCEDs. Novel surgical treatments focus on corneal neurotization and limbal cell reconstruction using novel scaffold materials and cell-sources. This review provides insights into future PCED treatments that build upon current management guidelines. Full article

Besides alternative surgical methods for bilateral limbal deficiency, such as KLAL (keratolimbal allograft), living-related conjunctival limbal allograft (LR-CLAL), and keratoprosthesis, regenerative medicine often necessitates the use of alternative sources of limbal cells in cases where access to fellow eye source cells is limited. Mucosal cells are most commonly used to restore limbal tissue in such scenarios. Current techniques involving mucosal cells include cultivated oral mucosal transplantation (COMT), oral mucosal graft transplantation (OMGT), and simple oral mucosal transplantation (SOMT). COMT requires suspension of cells and a culturing process that is time-consuming and cost-prohibitive. In contrast, OMGT requires solely a strip of mucosal graft for transplanting into the deficient eye. The most recently developed practice, SOMT, in which chopped biopsy tissue is transplanted into the deficient area, compensates for problems associated with both COMT and OMGT, making the process of addressing bilateral limbal deficiency easy, time-saving, and affordable. Although some undesirable outcomes, such as angiogenesis, can occur post-transplantation, and the ultimate goal of differentiation into limbal epithelial stem cells may not be achieved, mucosal cell sources can be a good alternative for stabilizing the ocular surface. Some studies emphasize that co-culturing limbal niches in mucosal cell cultures can enhance differentiation capability. This concept highlights the importance of the limbal environment in the differentiation process. In this review, we demonstrate the ongoing changes in surgical technique trends and how they have made mucosal cell transplantation easier and more effective for limbal regeneration. Full article

Background/Objectives: Evaluation of stem cell, keratin, retinoic acid metabolism markers and non-coding micro-RNAs (miRNAs) in conjunctival and corneal samples of patients with epithelial basal membrane dystrophy (EBMD), Salzmann nodular degeneration (SND), pterygium and congenital aniridia (CA), to detect similarities and differences in their pathogenesis. Methods: Impression cytology (IC) samples and corneal epithelial samples (CEs) of patients with EBMD, SND, pterygium, congenital aniridia, and healthy control subjects have been analyzed. The IC samples were subjected to qPCR, and the epithelial samples were subjected to qPCR and WB. Limbal epithelial stem cell markers, keratins, retinoic acid metabolism markers, and miRNAs were analyzed. Results: In conjunctival IC samples, PAX6 mRNA expression was significantly lower in EBMD, SND, pterygium, and CA compared to healthy controls (p ≤ 0.02). KRT13 mRNA expression was significantly higher in EBMD, SND, and pterygium (p ≤ 0.018), and FABP5 was increased in pterygium samples (p = 0.007). MiRNA-138-5p was significantly higher in aniridia samples than in normal controls (p = 0.037). In corneal epithelial samples, PAX6 protein, DSG1 mRNA and protein, miRNA-138-5p, and miR-204-5p expression were significantly lower in EBMD, SND, and pterygium samples than in controls (p ≤ 0.02). ALDHA1 mRNA expression was significantly lower (p < 0.0001), and FABP5 mRNA expression was significantly higher (p = 0.014) in pterygium samples than in controls. Conclusions: PAX6, DSG1, miR-138-5p, and miR-204-5p expression is decreased in the corneal epithelium of epithelial basal membrane dystrophy, Salzmann nodular degeneration, and pterygium subjects. In addition, there is a dysregulation of markers of the retinoic acid signaling pathway, such as ADH1A1 and FABP5, in the corneal epithelium of pterygium subjects. These changes may offer therapeutic targets in the treatment of these ocular surface diseases. Full article

Simple limbal epithelial transplantation (SLET) has emerged as an effective treatment option for limbal stem cell deficiency (LSCD). However, the precise molecular mechanisms underlying its success remain incompletely understood. This review delves into the proposed mechanisms involving the donor limbus, host microenvironment, and the amniotic membrane as a scaffold in SLET. The donor limbus contributes to SLET efficacy through various factors secreted by limbal epithelial stem cells, including hepatocyte growth factor (HGF), soluble Fms-like tyrosine kinase-1 (sFLT-1), and pigment epithelium-derived factor (PEDF), which support corneal healing and transparency. Additionally, the presence of melanocytes, immune cells, limbal fibroblasts, and adhesion molecules within the donor tissue helps preserve the integrity of the limbal niche. The host environment plays a critical role in supporting the transplanted stem cells, with mesenchymal stem cell-secreted factors promoting proliferation and differentiation. Although the amniotic membrane has traditionally been used as a scaffold, emerging evidence suggests that it may not always be necessary. Further studies are needed to validate this scaffold-free approach and to evaluate the vitality and functional contributions of individual components used in SLET. Understanding these complex interactions and molecular mechanisms sheds light on the importance of the donor tissue, host microenvironment, and scaffold in SLET, paving the way for the optimization of this technique for the effective treatment of LSCD. Full article

The World Health Organization estimates that approximately 285 million people suffer from visual impairments, around 5% of which are caused by corneal pathologies. Currently, the most common clinical treatment consists of a corneal transplant (keratoplasty) from a human donor. However, worldwide demand for donor corneas amply exceeds the available supply. Lamellar keratoplasty (transplantation replacement of only one of the three layers of the cornea) is partially solving the problem of cornea undersupply. Obviously, cell therapy applied to every one of these layers will expand current therapeutic options, reducing the cost of ophthalmological interventions and increasing the effectiveness of surgery. Mesenchymal stem cells (MSCs) are adult stem cells with the capacity for self-renewal and differentiation into different cell lineages. They can be obtained from many human tissues, such as bone marrow, umbilical cord, adipose tissue, dental pulp, skin, and cornea. Their ease of collection and advantages over embryonic stem cells or induced pluripotent stem cells make them a very practical source for experimental and potential clinical applications. In this review, we focus on recent advances using MSCs from different sources to replace the damaged cells of the three corneal layers, at both the preclinical and clinical levels for specific corneal diseases. Full article

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). The initial step involved the fabrication and characterization of CF and CF enriched with HA (CF-HA). Subsequently, T-LESCs were seeded on CF, CF-HA, and tissue culture plastic (TCP). Thereafter, the effect of these matrices on basic cellular function and tissue-specific extracellular matrix (ECM) deposition with or without MMC was evaluated. The viability and metabolic activity of cells cultured on CF, CF-HA, and TCP were found to be similar, while CF-HA induced the highest (p < 0.05) cell proliferation. It is notable that CF and HA induced cell growth, whereas MMC increased (p < 0.05) the deposition of collagen IV, fibronectin, and laminin in the T-LESC culture. The data highlight the potential of, in particular, immortalized cells and MMC for the development of biomimetic cell culture substrates, which could be utilized in ocular surface reconstruction following further in vitro, in vivo, and clinical validation of the approach. Full article

The limited availability of corneal tissue grafts poses significant challenges in the treatment of corneal blindness. Novel treatment utilizes stem cell grafts transplanted from the healthy side of the cornea to the damaged side. However, this procedure is only possible for those who have one-sided corneal blindness. Human stem cells offer promising potential for corneal tissue engineering, providing an alternative solution. Among the different types of stem cells, mesenchymal stem cells (MSCs) stand out due to their abundance and ease of isolation. Human MSCs can be derived from bone marrow, adipose, and umbilical cord tissues. Differentiating MSC toward corneal tissue can be achieved through several methods including chemical induction and co-culture with adult corneal cells such as human limbal epithelial stem cells (LESCs) and human corneal epithelial cells (hTCEpi). Adipose-derived stem cells (ADSCs) are the most common type of MSC that has been studied for corneal differentiation. Corneal epithelial cells are the most common corneal cell type targeted by researchers for corneal differentiation. Chemical induction with small molecules, especially bone morphogenetic protein 4 (BMP4), all-trans retinoic acid (ATRA), and epidermal growth factor (EGF), has gained more popularity in corneal epithelial cell differentiation. This review highlights the current progress in utilizing MSCs for corneal differentiation studies, showcasing their potential to revolutionize treatments for corneal blindness. Full article

The cornea is a vital component of the visual system, and its integrity is crucial for optimal vision. Damage to the cornea resulting from trauma, infection, or disease can lead to blindness. Corneal regeneration using mesenchymal stem cells (MSCs) and MSC-derived extracellular vesicles (MSC-EVs) offers a promising alternative to corneal transplantation. MSCs are multipotent stromal cells that can differentiate into various cell types, including corneal cells. They can also secrete a variety of anti-inflammatory cytokines and several growth factors, promoting wound healing and tissue reconstruction. This review summarizes the current understanding of the molecular and cellular mechanisms by which MSCs and MSC-EVs contribute to corneal regeneration. It discusses the potential of MSCs and MSC-EV for treating various corneal diseases, including corneal epithelial defects, dry eye disease, and keratoconus. The review also highlights finalized human clinical trials investigating the safety and efficacy of MSC-based therapy in corneal regeneration. The therapeutic potential of MSCs and MSC-EVs for corneal regeneration is promising; however, further research is needed to optimize their clinical application. Full article