Search Results (179)

Background/Objectives: Ocular graft-versus-host disease (oGVHD) is a chronic, immune-mediated complication of allogeneic hematopoietic stem cell transplantation that can progress to corneal ulceration or perforation. These cases are often refractory to standard therapy and present a high risk of graft failure after keratoplasty. We report a case of oGVHD-related corneal perforation successfully managed with a novel amniotic membrane-assisted “envelope” technique during corneal transplantation. Case Report: A 42-year-old man with chronic oGVHD and a full-thickness corneal perforation underwent urgent repair with a lamellar patch graft completely wrapped in cryopreserved amniotic membrane, followed by penetrating keratoplasty (PKP) using an amniotic membrane envelope surrounding the donor lenticule. Results: The amniotic membrane provided a 360° biological barrier that isolated graft antigens from the inflammatory environment while supporting epithelial healing and stromal remodeling. Despite recurrent inflammatory episodes and multiple procedures—including cataract extraction, pars plana vitrectomy, and multilayer amniotic membrane transplantation—the graft remained clear and stable at 12-month follow-up, achieving a best-corrected visual acuity of 20/40. Conclusions: The amniotic membrane envelope technique may represent a valuable adjunct in managing high-risk corneal perforations secondary to oGVHD. By combining immune modulation and regenerative support, this approach can enhance tectonic stability, reduce rejection risk, and promote durable surface recovery, potentially delaying or avoiding keratoprosthesis in refractory cases. Full article

The cornea maintains transparency by preserving immune and (lymph)angiogenic privilege through active suppression of inflammation and vascular invasion, a process centrally regulated by limbal epithelial stem cells (LESCs) located at the corneoscleral junction. Beyond renewing the corneal epithelium, LESCs maintain immune and vascular balance via extracellular matrix interactions and paracrine signalling, exerting predominantly anti-inflammatory and anti-(lymph)angiogenic effects in vivo. Disruption of the limbal niche by trauma, UV exposure, or genetic disorders such as aniridia leads to limbal stem cell deficiency (LSCD), chronic inflammation, loss of corneal avascularity, and vision loss. The identification of ABCB5 as a key LESC marker has clarified functional limbal subsets, highlighting ABCB5⁺ epithelial cells as mediators of repair, remodelling, and immune suppression, and positioning them as promising therapeutic targets for treatments that restore both epithelial integrity and corneal immune privilege. Full article

Background and Objectives: Corneal opacity is the fifth global cause of blindness and moderate-to-severe visual impairment due to scar tissue formation. The purpose of this study is to provide an integrated overview of the current state of corneal engineering strategies focused on the comparison with healthy corneas. It aims to identify engineering strategies that would result in functional corneas, providing real alternatives to donor corneal transplants. Materials and Methods: systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and according to the protocol with the ID: CRD420250654641 at the PROSPERO database. The focus question, prompted by considering the shortage of human corneal grafts, was: what is the performance of bioengineered corneal grafts in experimental animal models when compared with healthy eyes in the restoration of corneal anatomy and function? Results: Incorporating human corneal epithelial cells w/ or w/o human corneal stromal stem cells into a gelatin methacrylate and polyethylene glycol diacrylate matrix emerges as the leading option for epithelial layer regeneration. Human and bovine decellularized corneas, porcine corneal ECM in Gelatin methacrylate, dual layered collagen vitrigel and tissue-engineered human anterior hemi-corneas have shown promise for simultaneous regeneration of the corneal stromal and epithelial layers. Corneal stromal tissue regeneration could be positively impacted by transplantation with grafts derived from aligned self-lifting analogous tissue equivalents and collagen-based hydrogels. Finally, scaffolds of silk fibroin and human purified type I collagen represent promising approaches for corneal endothelial regeneration, though their effectiveness is contingent upon integration with endothelial cells. Conclusions: Collectively, these findings contribute to the growing body of evidence supporting the potential of tissue-engineered corneal substitutes as viable therapeutic options for corneal blindness and vision impairment. Assessing the optical and functional properties of the regenerated cornea should be a cornerstone in all studies aiming to evaluate their clinical effectiveness. Full article

Introduction: Allogeneic penetrating limbo-keratoplasty (limbo-PK) is one of the surgical methods for the treatment of limbal stem cell deficiency (LSCD). We report real-life results on different entities. Methods: Patients treated with limbo-PK at the Department of Ophthalmology of the University Medical Center Mainz were evaluated retrospectively. The primary endpoint was the epithelialization of the graft one year postoperatively. In addition, the postoperative best corrected visual acuity (BCVA), ocular concomitant diseases, drug treatment, and the need for further eye surgery postoperatively were examined. Results: We included 14 eyes of 13 patients (4 female) aged 59.8 ± 14.1 years who underwent limbo-PK between 2020 and 2024. Indications for limbo-PK included chemical burns (n = 4), blast injuries (n = 4), thermal burns (n = 2), trauma (n = 1) graft-versus-host disease (n = 1), and ectrodactyly-ectodermal dysplasia (EEC) (n = 1). The mean preoperative BCVA was 2.2 ± 0.6 logMAR (range: light perception to 0.7 logMAR). Four limbo-PK-grafts were HLA-typed. All limbo-PKs were combined with amniotic membrane transplantation; three with cataract surgery and one with tarsorrhaphy. Postoperatively, all patients received local immunosuppression, and 12 (85.7%) received additional systemic immunosuppression. At one-year follow-up mean BCVA increased to 1.0 ± 0.7 logMAR (range: 2.3 to 0.1, p-value = 0.03) and 11 of 14 eyes showed a functional graft with closed epithelium. In the further postoperative course, four patients needed a further Limbo-PK due to graft failure (n = 2), immune graft rejection after stopping local immunosuppressive therapy (n = 1) and perforation of the graft in a severe case of GvHd (n = 1). Conclusions: Limbo-PK is an effective surgical method for the treatment of LSCD. In our study cohort, we observed a significant improvement in mean BCVA one year postoperatively, with a functional, epithelialized graft achieved in 11 of 14 eyes. Full article

Berberine (BBR) has seen growing application in ophthalmology, yet the ocular toxicity of BBR and its metabolites remains poorly understood. This study aimed to evaluate the ocular toxicity of BBR and its major metabolite M1 and unravel their underlying mechanisms. Ocular toxicity was evaluated in human corneal epithelial cells and wild-type AB zebrafish. Mechanistic studies utilized fluorescence imaging, biochemical quantitative assays, and qPCR analyses in AB zebrafish and transgenic mitochondrial fluorescent zebrafish (strain Tg(Xla.Eef1a1:mlsEGFP)). Both BBR and M1 induced significant ocular toxicity across models, with BBR showing higher toxicity than M1. Mechanistic analyses revealed their toxicity stemmed from photoreceptor cell damage and Sirtuin 3 (SIRT3) inhibition, triggering a cascade of pathological events: mitochondrial dysfunction, oxidative stress, autophagic dysfunction, apoptosis, and inflammation. This study provides a reference for individualized risk assessment and clinical management of BBR-based therapies and paves the way for developing BBR derivatives with reduced ocular toxicity. Full article

Background: Severe dysfunction of the human limbus associated with limbal stem cell deficiency is a therapeutic challenge, especially when a structural alteration of the limbal niche is associated. Methods: We have evaluated seven decellularization protocols applied to 20 human sclero-corneal limbus, based on the use of SDS (protocol P1), SDS + NaCl (P2), SDS + triton X-100 + SDC + enzymatic treatment (P3), SDS + triton X-100 + SDC + enzymatic treatment + trypsin (P4), sulfobetains + DNAse (P5), sulfobetains + SDC + DNAse (P6) and SDC + DNAse (P7). The decellularization efficiency of each protocol, biocompatibility and safety, as well as their capability to support cell attachment and differentiation, were evaluated. Results: Results showed that the use of protocols P1 to P4, based on strong ionic detergents such as SDS, was not efficient for decellularizing the human limbus. Conversely, protocols P5, P6 and P7 removed more than 95% of DNA while preserving 60–100% of the extracellular matrix components. These protocols were biocompatible, as macrophages cultured with decellularized scaffolds were viable and differentiated to the pro-regenerative M2 phenotype (CD163/CD86 ratio > 2) without inducing a significant increase in reactive oxygen species (ROS). Protocols P6 and P7 supported cell attachment, survival and differentiation of corneal epithelial cells and four types of mesenchymal stem cells cultured on the surface of these scaffolds. Cellularized limbi showed positive expression of several limbal cell markers, especially in scaffolds decellularized with protocol P6. Conclusions: These results support the use of protocol P6 for the generation of human limbal substitutes by tissue engineering using decellularized human limbi. Future studies should determine the clinical potential of the regenerative biomaterial generated in patients with structural limbal damage, particularly in patients with chemical burns and aniridia, where conventional stem cell therapies fail. Full article

The assessment of donor corneas is currently based solely on central endothelial cell (EC) density, which potentially overlooks the transition zone (TZ) regenerative potential. Therefore, the present study characterizes TZ using multimodal imaging techniques to understand its regenerative potential and refine the assessment of donor tissue. Ex vivo donor corneas (n = 41) were examined using phase-contrast microscopy for EC counting and reflectance confocal microscopy (HRTII/RCM) for non-invasive visualization of the TZ. A subset of eight of these corneas underwent ultrastructural analysis using field-emission scanning electron microscopy (SEM) and immunostaining analysis using confocal microscopy. We observed a significant decrease in central EC density (p < 0.001) with increasing storage duration and donor age, while TZ width and TZ surface cell count remained stable. HRTII/RCM and SEM revealed distinct morphological differences (small, polygonal cells, irregular arrangement) in the TZ compared to the peripheral endothelium (PE). Immunostaining revealed elevated expression of progenitor markers (Nestin, ABCG2, SOX2, Lgr5, Vimentin) and reduced expression of endothelial markers (ZO1 and Na/K-ATPase) in the TZ compared to the PE, indicating the presence of a stem cell-like population. These findings suggest that TZ may contribute to endothelial cell regeneration, and HRTII/RCM could serve as a novel tool for TZ evaluation in low EC count donor corneas. Full article

Disorders of the cornea are responsible for a significant portion of preventable blindness worldwide. Various types of corneal transplantation procedures have successfully restored vision in many individuals; however, they carry the risk of graft failure due to immune rejection, endothelial cell dysfunction, infections and limbal stem cell deficiency. Thus, regenerative therapies of the cornea serve as promising alternatives or adjunct therapies. With improved understanding of limbal stem cell function and advancement in limbal stem cell culture technologies, major progress has been made in the in vivo and ex vivo cell-based therapies for treatment of corneal diseases. In this review, we summarize the recent developments achieved in cell-based therapeutics to target corneal epithelial, stromal, and endothelial cell disorders. Full article

Corneoscleral-ring-derived extracellular vesicles represent a potential therapeutic strategy for promoting in vitro corneal wound healing. In this study, we successfully isolated and characterized extracellular vesicles from human corneolimbal tissue obtained from 42 donors, with a mean age of 51.62 ± 15.56 years. Donor-related factors such as age, corneal endothelial cell density, and underlying systemic conditions did not confound extracellular vesicle size and concentration with mean peak size of 99.52 ± 13.00 nm by nanoparticle tracking analysis. Western blotting analysis revealed positive Alix, stable expression of CD9 and CD81, and variable expression of CD63. Limbal stem cell (LSC)-associated markers, i.e., ABCG2, p63, Notch-1, and Integrin α9 were positively detected in the isolated extracellular vesicles. Notably, Integrin α9 showed stable and relatively strong expression in all samples serving a specific marker of LSC-derived extracellular vesicles. Functional assays demonstrated that LSC-derived extracellular vesicles exhibited better wound healing potency compared to extracellular vesicles derived from mesenchymal stem cells (MSCs). These findings suggest that corneoscleral-ring-derived extracellular vesicles express distinct LSC markers, including Integrin α9, and hold significant potential for application in corneal wound healing and ocular surface regeneration. Full article

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

Corneal endothelial dysfunction is a leading cause of vision impairment globally, traditionally managed through donor-dependent keratoplasty procedures. However, limitations in donor tissue availability, surgical complexity, and long-term graft survival have prompted the development of cell-based regenerative therapies. Among these, corneal endothelial cells (CECs) injection therapy has emerged as a minimally invasive alternative, offering the potential to restore endothelial function. This review provides a comprehensive analysis of recent advances in bioengineering strategies for CECs therapy, including cell sourcing from donor tissue, pluripotent stem cells, and transdifferentiated somatic cells; optimization of culture conditions and substrates; and delivery protocols that enhance cell adhesion and survival. We further examine clinical trial outcomes and propose future directions for clinical translation. The convergence of cell biology, biomaterials engineering, and translational medicine positions CECs injection therapy as a transformative solution to corneal blindness. 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

Corneal regeneration has gained growing interest in recent years, largely due to the limitations of conventional treatments and the persistent shortage of donor tissue. Among the emerging strategies, extracellular vehicles (EVs), especially those derived from mesenchymal stromal cells (MSCs), have shown great promise as a cell-free therapeutic approach. These nanoscale vesicles contribute to corneal healing by modulating inflammation, supporting epithelial and stromal regeneration, and promoting nerve repair. Their therapeutic potential is largely attributed to the diverse and bioactive proteomic cargo they carry, including growth factors, cytokines, and proteins involved in extracellular matrix remodeling. This review presents a comprehensive examination of the proteomic landscape of EVs in the context of corneal regenerative medicine. We explore the biological functions of EVs in corneal epithelial repair, stromal remodeling, and neurodegeneration. In addition, we discuss advanced proteomic profiling techniques such as mass spectrometry (MS) and liquid chromatography–mass spectrometry (LC-MS/MS), which have been used to identify and characterize the protein contents of EVs. This review also compares the proteomic profiles of EVs derived from various MSC sources, including adipose tissue, bone marrow, and umbilical cord, and considers how environmental cues, such as hypoxia and inflammation, influence their protein composition. By consolidating current findings, this article aims to provide valuable insights for advancing the next generation of cell-free therapies for corneal repair and regeneration. Full article

Cell-based therapies emerge as potential treatment options for various debilitating diseases. Preclinical research and clinical studies involving cells increased exponentially in the past decade. In addition to cell-based approaches, the use of extracellular vesicles (EVs), which are released by nearly all cell types, emerged as a promising cell-free alternative. Those approaches are also being explored in the field of ophthalmology. Several clinical trials involving EVs are underway to develop potential treatments for advanced ocular surface diseases, including corneal disorders, injuries, and dry eye disease. The cargo carried by EVs has been shown to include a diverse array of functional molecules such as transcription factors, cytokines, growth factors, mRNA, tRNA, rRNA, miRNA, and fragments of dsDNA. While the molecular composition of EVs is already well characterised, the specific activity of these molecules upon delivery to recipient cells remains poorly understood. In this review, we summarise recent studies investigating the bioactive molecules within EVs shown to influence or modulate cellular activity on the ocular surface. Among these, various miRNAs have most commonly been identified as therapeutic agents targeting distinct molecular pathways. The EVs studied were predominantly derived from various mesenchymal stem cells. Full article