We explore the interaction between corneal immunity and mesenchymal stem/stromal cells (MSCs) and their potential in treating corneal and ocular surface disorders. We outline the cornea's immune privilege mechanisms and the immunomodulatory substances involved. In this realm, MSCs are characterized by their immunomodulatory properties and regenerative potential, making them promising for therapeutic application. Therefore, we focus on the role of MSCs in immune-mediated corneal diseases such as dry eye disease, corneal transplantation rejection, limbal stem cell deficiency, and ocular graft-versus-host disease. Preclinical and clinical studies demonstrate MSCs' efficacy in promoting corneal healing and reducing inflammation in these conditions. Overall, we emphasize the potential of MSCs as innovative therapies in ophthalmology, offering promising solutions for managing various ocular surface pathologies.

Retinal neurodegeneration leads to irreversible blindness due to the mammalian nervous system's inability to regenerate lost neurons. Efforts to regenerate retina involve two main strategies: stimulating endogenous cells to reprogram into neurons or transplanting stem-cell derived neurons into the degenerated retina. However, both approaches must overcome a major barrier in getting new neurons to grow back down the optic nerve and connect to appropriate visual targets in environments that differ significantly from developmental conditions. While immune privilege has historically been associated with the central nervous system, an emerging literature highlights the active role of immune cells in shaping neurodegeneration and regeneration. This review explores the neuroimmune interface in retinal repair, dissecting how immune interactions influence glial reprogramming, transplantation outcomes, and axonal regeneration. By integrating insights from regenerative species with mammalian models, we highlight novel immunomodulatory strategies to optimize retinal regeneration.

Immunology depends on maintaining a delicate balance within the human body, and disruptions can result in conditions such as autoimmune diseases, immunodeficiencies, and hypersensitivity reactions. This balance is especially crucial in transplantation immunology, where one of the primary challenges is preventing graft rejection. Such rejection can lead to organ failure, increased patient mortality, and higher healthcare costs due to the limited availability of donor tissues relative to patient needs. Xenotransplantation, like using porcine corneas for human transplants, offers a potential solution to the donor tissue shortage but faces substantial immunological rejection issues. To prevent rejection in both allo- and xenotransplantation, a deep understanding of how the body maintains immunological balance is essential, particularly since achieving tolerance to non-self tissues is considered the "holy grail" of the field. The cornea, the most frequently transplanted solid organ, has a high acceptance rate due to its immune-privileged status and serves as an ideal model for studying graft rejection mechanisms that disrupt tolerance. However, multiple immune pathways complicate our understanding of these mechanisms. This review examines the rejection mechanisms in corneal transplantation, identifying key cells involved and potential therapeutic strategies to induce and maintain immunological tolerance in both allo- and xenografts across various transplants.

Inherited retinal diseases (IRDs) are genetic disorders characterized by progressive photoreceptor function loss, often leading to significant visual impairment. Uveitis has been increasingly recognized in the clinical course of some IRDs. Despite advances in understanding the genetic causes and pathophysiology of IRDs, gaps remain in understanding the roles of inflammation and autoimmunity in IRD and IRD-associated uveitis. This review discusses IRD-associated uveitis, including anterior, intermediate, posterior, and panuveitis, as well as complications such as cystoid macular edema and retinal vasculitis. In patients with IRD-associated uveitis, mutations affecting protein function in cilia or photoreceptor outer segments suggest a universal autoimmune mechanism triggered by the immunogenicity of shedding photoreceptor discs. Notably, in patients where uveitis is the initial sign, CRB1 mutations are often implicated, likely due to the compromised blood-retina barrier function or alterations in the external limiting membrane. Other mechanisms leading to uveitis preceding IRD diagnosis include ALPK1 mutations, which activate the proinflammatory NF-κB pathway, CAPN5 mutations, which lead to dysfunction of the innate and adaptive immune systems, and VCAN1 mutations, which elicit immunogenicity due to irregularities in vitreous modeling. Understanding these mechanisms could enhance the development of innovative treatments that target personalized inflammation pathways in IRDs.

For patients with bilateral age-related cataracts, sequential phacoemulsification and intraocular lens implantation is a common treatment. However, it remains unclear whether surgery on the first eye has an impact on the second eye, as current research results are inconsistent. This study will explore whether surgery on one eye affects the non-operated eye through aqueous humor cytokines and metabolomic analyses in the second eye.

A rabbit model of unilateral phacoemulsification and intraocular lens implantation was established. The experimental group consisted of 15 rabbits undergoing this procedure. Postoperatively, rabbits were divided into five subgroups (three rabbits per subgroup), and aqueous humor was collected from both the operated and non-operated eyes at 1 day, 3 days, 1 week, 2 weeks, and 3 weeks after surgery. Additionally, 5 rabbits were selected as a control group, from which aqueous humor was extracted. Levels of IL-1a, IL-1β, IL-2, IL-4, IL-6, IL-8, IFN-γ, TNF-α, MCP-1, and VEGF in the aqueous humor were compared. In the clinical study, preoperative aqueous humor samples were collected from 22 patients undergoing bilateral phacoemulsification and intraocular lens implantation. Among them, 11 patients were tested for the aforementioned 10 cytokines, while the other 11 patients underwent untargeted metabolomics research.

In the animal experiment, levels of all 10 cytokines in the operated eyes were significantly higher compared to both the control and non-operated eyes groups (P < 0.05). In the non-operated eyes, IL-1β and IL-2 levels were also elevated compared to the control (P < 0.05); however, no statistically significant differences were observed between the non-operated eyes and the control group at postoperative time points of 1 day, 3 days, 1 week, 2 weeks, and 3 weeks. In the clinical study, no significant differences were found in cytokine levels between the two eyes. In the untargeted metabolomics analysis, 354 metabolites showed differential expression, 280 were upregulated and 74 were downregulated. Notably, Adenine and 2-Aminopurine were significantly downregulated, highlighting Purine metabolism as the most impacted pathway.

Animal experiments showed a significant increase in IL-1β and IL-2 levels in the non-operated eyes postoperatively, reflecting systemic and local inflammatory responses. In clinical experiments, although no significant changes in cytokines were observed in the aqueous humor of both eyes, differential expression of metabolites indicated metabolic adjustments in the non-operated eye following surgery on the first eye. These findings reveal that unilateral cataract surgery may affect the stability of the intraocular environment in the contralateral eye, suggesting that in staged bilateral surgeries, potential metabolic changes in the non-operated eye and their clinical significance should be considered. This result provides important reference value for optimizing postoperative management strategies, reducing complications, and determining the timing for bilateral surgeries, warranting further investigation.

As the prevalence of diabetes mellitus increases each year, its most common microvascular complication, diabetic retinopathy (DR), is also on the rise. DR is now regarded as an inflammatory disease in which innate immunity plays a crucial role, and a large number of innate immune cells with associated cytokines are involved in the pathologic process of DR. The role of adaptive immunity in DR is seldom mentioned, probably due to the general perception of the immune privileged environment of the retina; however, in recent years there has been a gradual increase in research on the role of adaptive immunity in DR, and with the discovery of the retinal lymphatic system, it seems that the role of adaptive immunity can no longer be ignored. Here, we discuss the immunosuppressive environment of the retina, the phenomenon and potential mechanisms of lymphocyte infiltration in DR, and the role of the adaptive immune system in the diabetic retina, which may point the way for future research.

Allograft rejection remains a major cause of failure in high-risk corneal transplants, but the underlying mechanisms are not fully understood. This study aimed to investigate the contribution of transplantation stress-induced cellular senescence to corneal allograft rejection and to elucidate the associated molecular mechanisms.

Age-matched murine corneal transplantation models were established. Cellular senescence was evaluated using senescence-associated β-galactosidase (SA-β-Gal) staining, western blot, and immunofluorescence staining. The role of cellular senescence in corneal allograft rejection was analyzed using p16 knockout mice and adoptive transfer experiments. Senolytic treatment with ABT-263 was administered intraperitoneally to evaluate its effects on corneal allograft rejection. RNA sequencing and pharmacological approaches were employed to identify the underlying mechanisms.

Surgical injury induced a senescence-like phenotype in both donor corneas and recipient corneal beds, characterized by an increased accumulation of SA-β-Gal-positive cells in the corneal endothelium and stroma and elevated expression of senescence markers p16 and p21. Using genetic and adoptive transfer models, transplantation stress-induced senescence was shown to exacerbate corneal allograft rejection. Importantly, clearance of senescent cells by ABT-263 significantly suppressed ocular alloresponses and immune rejection. Mechanistically, RNA sequencing and loss-of-function experiments demonstrated that the anti-rejection effects of senolytic treatment were closely dependent on angiotensin-converting enzyme 2 (ACE2).

These findings highlight transplantation stress-induced senescence as a pivotal pathogenic factor in corneal allograft rejection. Senolytic therapy emerges as a potential novel strategy to mitigate transplant rejection and improve corneal allograft survival.

Targeted therapy is a promising approach to improve the treatment of tumors, including ocular malignancies. Current therapies, such as radiotherapy and surgery, often lead to serious damage to vision or to loss of the eye. New approaches have examined nanoparticles for use as targeted delivery vehicles for drugs. A newly-developed virus-like drug conjugate is a promising nanoparticle with a defined target: the novel virus-like particle-photosensitizer conjugate Belzupacap sarotalocan (Bel-sar, previous name AU-011).

In this review, we summarize the application of this novel light-activated virus-like particle conjugate in pre-clinical and clinical studies and discuss its potential to treat ocular malignancies, such as uveal melanoma and conjunctival melanoma. We furthermore discuss the combination with immunotherapy and its application on pigmented and non-pigmented tumors as well as its effect on macrophage polarization, which is important to achieve effective results in immunotherapy.

Belzupacap sarotalocan (Bel-sar) is a promising targeted drug carrier that enhances tumor-specific delivery and minimizes off-target effects. Its photodynamic therapy effectively treats pigmented and non-pigmented tumors while inducing immunogenic cell death through DAMP exposure, triggering local and systemic immune responses. Combining Bel-sar PDT with immunotherapy improves efficacy in preclinical models, warranting further clinical investigation.

Due to its unique physiological structure and functions, the eye has received considerable attention in the field of adeno-associated virus (AAV) gene therapy. Inherited retinal degenerative diseases, which arise from pathogenic mutations in mRNA transcripts expressed in the eye's photoreceptor cells or retinal pigment epithelium (RPE), are the most common cause of vision loss. However, current retinal gene therapy mostly involves subretinal injection of therapeutic genes, which treats a limited area, entails retinal detachment, and requires sophisticated techniques. Intravitreal (IVT) injection provides an alternative method with less invasion and more convenience for retinal gene therapy. In the present study, we performed a directed evolution via DNA shuffling in RHO-GFP mice and identified a novel recombinant AAV vector (AAV-M04) suitable for IVT injection in the gene delivery of retinal tissue. Compared with AAV2, AAV9, and AAV2.7m8, AAV-M04 vector exhibited higher transduction efficiency in retinal ganglion cell line-5 (RGC-5) cells as well as in human embryonic stem cell derived retinal organoids. Importantly, when delivered via IVT injection in mice, the AAV-M04 vector also showed better delivery efficiency of transgene as indicated by the red fluorescence protein mScarlet. The red fluorescence was distributed in a wider retinal area of AAV-M04 injected mice, suggesting the potent retinal targeting of AAV-M04 vector. In addition, AAV-M04 qualities including the packaging efficiency, the thermal stability, and the capsid integrity were superior to controls, which were important in drug manufacture. In summary, we screened a novel AAV-M04 vector with great retinal-targeting via IVT injection, which provides the potential of AAV-M04 for effective gene therapy of retinal diseases.

Rhegmatogenous retinal detachment (RRD) is a sight-threatening condition involving retinal detachment and the accumulation of fluid in the subretinal space. Proliferative vitreoretinopathy (PVR) is a pathologic complication that develops after RRD surgery, and approximately 5-10% of RRD cases develop post-operative PVR. Prolonged inflammation in the wound healing process, epithelial-mesenchymal transition (EMT), retinal pigment epithelial (RPE) cell migration and proliferation, and epiretinal, intraretinal, and subretinal fibrosis are typical in the formation of PVR. RPE cells undergo EMT and become fibroblast-like cells that migrate to the retina and vitreous, promoting PVR formation. Fibroblasts transform into myofibroblasts, which promote fibrosis by overproducing the extracellular matrix (ECM). RPE cells, fibroblasts, glial cells, macrophages, T lymphocytes, and increased ECM production form contractile epiretinal membranes. Cytokine release, complement activation, RPE cells, glial cells, and endothelial cells are all involved in retinal immune responses. Normally, wounds heal within 4 to 6 weeks, including hemostasis, inflammation, proliferation, and remodeling phases. Properly initiated inflammation, complement activation, and the function of neutrophils and glial cells heal the wound in the first stage. In a retinal wound, glial cells proliferate and fill the injured area. Gliosis tries to protect the neurons and prevent damage, but it becomes harmful when it causes scarring. If healing is complicated, prolonged inflammation leads to pathological fibrosis. Currently, there is no preventive treatment for the formation of PVR, and it is worth studying in the future.

Defining the mechanism of immune modulation by mesenchymal stromal cells (MSCs) from distinct anatomical tissues is of great translational interest. The human cornea is an immunologically privileged organ, and the mechanism of immunoregulation of cornea-derived MSCs (cMSCs) is currently unknown. We investigated cMSCs derived from the corneas of 5 independent human donorS for their fitness and mechanism of action in suppressing T cells. cMSCs display the immunophenotype CD45-CD73+CD105+CD90+CD44+ and robust in vitro growth. 30-plex secretome analysis identified that cMSCs innately secrete specific molecules in a dose-dependent manner. cMSCs do not express or upregulate costimulatory but do upregulate coinhibitory molecules upon stimulation with interferon γ (IFNγ). cMSCs inhibit T-cell proliferation in contact-dependent co-cultures, which can be predicted by a unique secretome signature. In addition, co-culturing in a 2-chamber transwell system has demonstrated that cMSCs also inhibit T-cell proliferation in a non-contact-dependent manner. Mechanistic analysis has demonstrated that activated T cells effectively induce indoleamine 2,3-dioxygenase (IDO) but not other enzymes of the tryptophan metabolic pathway in cMSCs. Silencing of IDO in cMSCs reduces their fitness to suppress T cells. These results provide evidence that in cMSCs, one of the principal mechanisms of immunosuppression on T cells is through IDO. These results suggest that MSCs derived from the human cornea display immunoregulatory properties and, thus, may play a role in maintaining the immune-privileged niche of the cornea.

Retinal diseases can severely impair vision and even lead to blindness, posing significant threats to both physical and mental health. Physical retinal regenerative therapies are poised to revolutionize the treatment of various disorders associated with blindness. However, these therapies must overcome the challenges posed by the protective inner and outer blood‒retinal barriers. Nanotechnology applications in ophthalmology have shown great potential in addressing the issue of drug delivery to the eye. Moreover, nanotechnology-based therapeutics can have profound clinical impacts on retinopathy, particularly retinal regeneration, thereby improving patient outcomes. Continuous advancements in nanotechnology are being applied to regenerate lost or damaged eye tissues and to treat vision loss and blindness caused by various retinal degenerative diseases. These approaches can be categorized into three main strategies: i) nanoparticles for delivering drugs, genes, and other essential substances; ii) nanoscaffolds for providing biocompatible support; and iii) nanocomposites for enhancing the functionality of primary or stem cells. The aim of this comprehensive review is to present the current understanding of nanotechnology-based therapeutics for retinal regeneration, with a focus on the perspective functions of nanomaterials.

COVID-19, caused by SARS-CoV-2, has presented formidable challenges to global health since its emergence in late 2019. While primarily known for respiratory symptoms, it can also affect the ocular surface. This review summarizes the effects of SARS-CoV-2 on ocular surface immunity and inflammation, focusing on infection mechanisms, immune responses, and clinical manifestations. Ocular symptoms, though uncommon, include conjunctivitis, dry eye, and blurred vision. SARS-CoV-2 binds to ACE2 receptors in ocular surface epithelial cells, facilitating viral entry, replication, and local dissemination. The innate immune responses involving corneal epithelial cells and immune cells are discussed, alongside mechanisms of antigen presentation and adaptive immunity. The review also examines the roles of cytokines and chemokines in mediating ocular surface inflammation and explores the impact of cytokine storms and chronic inflammation on ocular health. Additionally, the interplay between systemic and ocular immune responses is highlighted, analyzing how systemic COVID-19 inflammation influences ocular surface health. These insights underscore the broader implications of COVID-19 beyond localized ocular infection. By consolidating current findings, this review aims to guide preventive and therapeutic strategies while identifying directions for future research to mitigate the ocular consequences of COVID-19.

The dysregulation of the innate immune system plays a crucial role in the development of Diabetic Retinopathy (DR). To gain an insight into the underlying mechanism of DR, it is essential to identify specific biomarkers associated with immune cell infiltration.

In this study, we retrieved the GSE94019 and GSE60436 datasets from the Gene Expression Omnibus (GEO) database. By utilizing CIBERSORT, MCPcounter, and xCell algorithms, we conducted a comprehensive analysis of the immune cell infiltration landscape in DR. The limma package was employed to identify Differentially Expressed Necroptosis-related Genes (DENRGs). Subsequently, enrichment analysis was performed to investigate the potential functions of the DENRGs. To identify the core DENRGs, the CytoHubba plug-in in Cytoscape software was utilized. The expression levels of these core DENRGs were verified in an independent dataset.

Our analysis identified 213 DENRGs, and among them, Platelet-derived Growth Factor subunit A (PDGFA) was identified as a core DENRG. Notably, the expression of PDGFA was found to be upregulated in DR, and this finding was further validated in the GSE102485 dataset. Additionally, the results of GSVA and GSEA revealed that in the high PDGFA group, there was activation of pathways related to inflammation and the immune system. Moreover, analysis of immune infiltration demonstrated a significant association between PDGFA gene expression and the infiltration levels of specific immune cells, including basophils, macrophages M1, macrophages, neutrophils, monocytes, NK cells, and B cells.

The involvement of neutrophils in the development and progression of DR is suggested. PDGFA has emerged as a potential marker and is linked to the infiltration of immune cells in DR. These findings shed new light on the underlying mechanisms of DR.

To meet the prodigious bioenergetic demands of the photoreceptors, glucose and other nutrients must traverse the retinal pigment epithelium (RPE), a polarised monolayer of cells that lie at the interface between the outer retina and the choroid, the principal vascular layer of the eye. Recent investigations have revealed a metabolic ecosystem in the outer retina where the photoreceptors and RPE engage in a complex exchange of sugars, amino acids, and other metabolites. Perturbation of this delicate metabolic balance has been identified in the aging retina, as well as in age-related macular degeneration (AMD), the leading cause of blindness in the Western world. Also common in the aging and diseased retina are elevated levels of cytokines, oxidative stress, advanced glycation end-products, increased growth factor signalling, and biomechanical stress - all of which have been associated with metabolic dysregulation in non-retinal cell types and tissues. Herein, we outline the role of these factors in retinal homeostasis, aging, and disease. We discuss their effects on glucose, mitochondrial, lipid, and amino acid metabolism in tissues and cell types outside the retina, highlighting the signalling pathways through which they induce these changes. Lastly, we discuss promising avenues for future research investigating the roles of these pathological conditions on retinal metabolism, potentially offering novel therapeutic approaches to combat age-related retinal disease.

Genetic medicines, including CRISPR/Cas technologies, extend tremendous promise for addressing unmet medical need in inherited retinal disorders and other indications; however, there remain challenges for the development of therapeutics. Herein, we evaluate genome editing by engineered Cas9 ribonucleoproteins (eRNP) in vivo via subretinal administration using mouse and pig animal models. Subretinal administration of adenine base editor and double strand break-inducing Cas9 nuclease eRNPs mediate genome editing in both species. Editing occurs in retinal pigmented epithelium (RPE) and photoreceptor cells, with favorable tolerability in both species. Using transgenic reporter strains, we determine that editing primarily occurs close to the site of administration, within the bleb region associated with subretinal injection. Our results show that subretinal administration of eRNPs in mice mediates base editing of up to 12% of the total neural retina, with an average rate of 7% observed at the highest dose tested. In contrast, a substantially lower editing efficiency was observed in minipigs; even with direct quantification of only the treated region, a maximum base editing rate of 1.5%, with an average rate of <1%, was observed. Our data highlight the importance of species consideration in translational studies for genetic medicines targeting the eye and provide an example of a lack of translation between small and larger animal models in the context of subretinal administration of Cas9 eRNPs.

Retinitis pigmentosa (RP) is characterized by degeneration of rod and cone photoreceptors that progresses to irreversible blindness. Now, there are no mutation-agnostic approaches to treat RP. Here, we utilized a single adeno-associated virus (AAV)-based CRISPR activation system to activate phosphodiesterase 6B (Pde6b) to mitigate the severe degeneration in Pde6anmf363 mice. We demonstrate that transcriptional activation of Pde6b can rescue the loss of Pde6a, with preservation of retinal structure, restoration of electroretinography responses, and improvement of visual function as assessed by optokinetic response and looming-induced escape behaviors. These findings demonstrate the therapeutic potential of a dCasMINI-mediated activation strategy that provides a mutation-independent treatment for retinal degeneration. This study offers a promising therapeutic approach for RP and potentially other forms of genetic diseases.

To elucidate the etiology of infectious uveitis through the comprehensive analysis of keratic precipitates (KPs) using in vivo confocal microscopy (IVCM).

Cross-sectional, observational case series.

This single-center, cross-sectional study was conducted at a tertiary care eye hospital from January 2021 to October 2023. It involved a detailed ophthalmologic evaluation of all subjects and included a total of 46 eyes from 36 subjects who were diagnosed with infectious uveitis. IVCM, specifically utilizing the HRT II Rostock corneal module, was employed to study the biomicroscopic morphology of KPs. The categorization of KPs was based on cell size, morphology, and reflection.

Cells of KPs were assessed for size, morphology, and reflection through in vivo confocal microscopy. Patients, ranging in age from 13 to 80 years (median 51 years), exhibited diverse morphologic forms of KPs. Neutrophil-dominated KPs with uniform size were predominantly observed in bacterial and fungal endophthalmitis cases (19/19, 100 %), accompanied by small numbers of mononuclear-macrophages in three eyes (3/19, 15.8 %). Viral uveitis cases displayed a broader array of immune cell types, including characteristic striated or dendritic cells in all eyes (27/27, 100 %). Lymphocytes were commonly present (24/27, 88.9 %), forming clusters in sixteen eyes and dispersed in the corneal endothelium below the midline in eight eyes. Neutrophil infiltration was notable in three cytomegalovirus-infected eyes (3/27, 11.1 %). A marked increase in sub-basal corneal epithelial Langhans cells was associated with viral uveitis.

Neutrophil-dominated KPs strongly indicate endogenous bacterial or fungal endophthalmitis, while the presence of dendritic cells and lymphocytes in KPs is suggestive of viral uveitis. In vivo confocal microscopy emerges as a crucial tool for differentiating the etiologic diagnosis of infectious uveitis.

Gene augmentation therapy is a promising treatment for incurable, blinding inherited retinal diseases, and intravitreal delivery is being studied as a safe alternative to subretinal injections. Adeno-Associated Viruses (AAV) are commonly-used vectors for ocular gene augmentation therapy. Naturally occurring pre-operative exposure and infection with AAV could result in presence of neutralizing antibodies (NAB's) in patients' serum, and may affect the safety and efficacy of treatment. Our aim was to characterize the humoral response against AAV pre- and post-intravitreal delivery of AAV2.7m8 vectors in a naturally-occurring sheep model of CNGA3 achromatopsia. Serial serum neutralization assays were performed to screen sheep for pre-exiting anti-AAV2 NAB's, and to assess the effect of intravitreal AAV2.7m8 injection on post-operative NAB titers and intraocular inflammation in sheep. The effect of viral dose and transgene type were also assessed. Serological screening revealed pre-operative seropositivity in 21.4% of animals, with age being a risk factor for the presence of anti-AAV2 NAB's. NAB titers increased following intravitreal AAV administration in the majority of sheep. There was no significant difference in the degree of post-operative serum neutralization between pre-operatively seronegative sheep and those with pre-existing antibodies. However, only sheep with pre-existing antibodies presented with signs of post-operative inflammation. We conclude that pre-existing anti-AAV2 NAB's do not affect the level of post-operative NAB titers; however, they increase the risk of post-operative ocular inflammation. Our results could have implications for the management of AAV-mediated ocular gene therapies, a technology being increasingly studied and used in patients.

Systemic sclerosis (SSc) is a chronic multisystemic disease characterized by immunological activation, diffuse vasculopathy, and generalized fibrosis exhibiting a variety of symptoms. A recognized precursor of SSc is Raynaud's phenomenon, which is part of the very early disease of systemic sclerosis (VEDOSS) in combination with nailfold videocapillaroscopy (NVC) impairment. The pathophysiology of ocular involvement, alterations in internal organs, and body integumentary system involvement in SSc patients are complicated and poorly understood, with multiple mechanisms presumptively working together. The most prevalent ocular symptoms of SSc are abnormalities of the eyelids and conjunctiva as well as dry eye syndrome, due to fibroblasts' dysfunction and inflammation of the ocular surface. In particular, lagophthalmos, blepharophimosis limitation of eyelid motion, eyelid telangiectasia, and rigidity or tightening of the lids may affect up to two-third of the patients. In addition, reduction in central corneal thickness, iris defects and higher rates of glaucoma were reported. In the first reports based on retinography or fluorescein angiography, about 50% of SSc patients showed signs of vascular disease: peripheral artery occlusion, thinning of retinal pigment epithelium and choroidal capillaries, ischemic areas surrounded by intraretinal extravasation and microaneurysms, and peripheral capillary non-perfusion. Successively, thanks to the advent of optical coherence tomography angiography (OCTA), several studies highlighted significant impairment of either the choriocapillaris and retinal vascular plexuses, also correlating with NVC involvement and skin disease, even in VEDOSS disease. Given the sensitivity of this technique, ocular micro-vasculopathy may act as a tool for early SSc identification and discriminate between disease stages.

Deficient Angiopoietin-Tie2 signaling is linked to ocular hypertension in glaucoma. Receptor Tie2/TEK expression and signaling at Schlemm's canal (SC) is indispensable for canal integrity and homeostatic regulation of aqueous humor outflow (AHO) and intraocular pressure (IOP), as validated by conditional deletion of Tie2, its ligands (Angpt1, Angpt2 and Angpt3/4) or regulators (Tie1 and PTPRB/VE-PTP). However, these Tie2/TEK knockouts and conditional knockouts are global or endothelial, preventing separation of systemic and ocular vascular defects that impact retinal or renal integrity. To develop a more targeted model of ocular hypertension induced by selective knockdown of Tie2/TEK expressed in SC, we combined the use of viral vectors to target the canal, and two distinct gene-editing strategies to disrupt the Tie2 gene. Adeno-associated virus (AAV2) is known to transduce rodent SC when delivered into the anterior chamber by intracameral injection. First, delivery of Cre recombinase via AAV2.Cre into R26tdTomato/+ reporter mice confirmed preferential and stable transduction in SC endothelium. Next, to disrupt Tie2 expression in SC, we injected AAV2.Cre into homozygous floxed Tie2 (Tie2FL/FL) mice. This led to attenuated Tie2 protein expression along the SC inner wall, decreased SC area and reduced trabecular meshwork (TM) cellularity. Functionally, IOP was significantly and steadily elevated, whereas AHO facility was reduced. In contrast, hemizygous Tie2FL/+ mice responded to AAV2.Cre with inconsistent and low IOP elevation, corroborating the dose-dependency of ocular hypertension on Tie2 expression/activation. In a second model using CRISPR/SaCas9 genome editing, wild-type C57BL/6 J mice injected with AAV2.saCas9-sgTie2 showed similar selective SC transduction and comparable IOP elevation in course and magnitude to that induced by AAV2.Cre in Tie2FL/FL mice. Together, our findings, demonstrate that selective Tie2 knockdown in SC is a targeted strategy that reliably induces chronic ocular hypertension and reproduces glaucomatous damage to the conventional outflow pathway, providing novel models of SC-Tie2 signaling loss valuable for preclinical studies.

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.

Anterior chamber-associated immune deviation (ACAID) is an active immunotolerance mechanism, which is induced by placing antigen into the anterior eye chamber as long as a major surgical trauma is avoided. For this reason, ACAID may be a major contributor to the favorable immunologic outcomes in Descemet membrane endothelial keratoplasty (DMEK). Rodent models have demonstrated the importance of a functional spleen for the development of an ACAID.

This study aimed to investigate whether splenectomy leads to increased rejection rates after DMEK in humans.

A retrospective evaluation was conducted on the course following DMEK at the Eye Center, Medical Center, University of Freiburg, for patients with a self-reported history of splenectomy compared to patients without this condition. Potential study patients were contacted by mail. A questionnaire to self-report splenectomy and the time thereof was sent out. The medical records of all consenting patients at the Eye Center were reviewed for graft survival and immune reactions.

We asked 1818 patients after DMEK to report their history of splenectomy. A total of 1340 patients responded and were included in the study. Of these 1340 patients, 16 (1.2%) reported a history of splenectomy (ie, 26 DMEKs, with 10 patients being transplanted in both eyes and 6 patients being transplanted in 1 eye; median age at surgery 73.7, range 66.7-76.1 y). The remaining patients (1324 patients, ie, 1941 eyes) served as controls, with 1941 DMEKs (median age at surgery 71.5, range 64.1-77.2 y). Five (19%) out of the 26 eyes from the splenectomy group required a second transplant due to dislocation (n=2.8%), failure (n=2.8%), and rejection (n=1.4%). Kaplan-Meier analysis revealed no relevant difference compared with controls.

Our results suggest that splenectomy has no major effect on the outcome following DMEK. Subsequent, ACAID may not be the main reason for the favorable immunological outcomes in DMEK, or the camero-splenic axis may be subordinate in humans. However, we only included 16 patients who underwent splenectomy, so it might be possible that we missed a minor effect.

Microbial keratitis (MK) is an infection of the cornea, caused by bacteria, fungi, parasites, or viruses. MK leads to significant morbidity, being the fifth leading cause of blindness worldwide. There is an urgent requirement to better understand pathogenesis in order to develop novel diagnostic and therapeutic approaches to improve patient outcomes. Many in vitro, ex vivo and in vivo MK models have been developed and implemented to meet this aim. Here, we present current in vitro and ex vivo MK model systems, examining their varied design, outputs, reporting standards, and strengths and limitations. Major limitations include their relative simplicity and the perceived inability to study the immune response in these MK models, an aspect widely accepted to play a significant role in MK pathogenesis. Consequently, there remains a dependence on in vivo models to study this aspect of MK. However, looking to the future, we draw from the broader field of corneal disease modelling, which utilises, for example, three-dimensional co-culture models and dynamic environments observed in bioreactors and organ-on-a-chip scenarios. These remain unexplored in MK research, but incorporation of these approaches will offer further advances in the field of MK corneal modelling, in particular with the focus of incorporation of immune components which we anticipate will better recapitulate pathogenesis and yield novel findings, therefore contributing to the enhancement of MK outcomes.

Retinal degeneration diseases, such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP), initially manifest as dysfunction or death of the retinal pigment epithelium (RPE). Subretinal transplantation of human pluripotent stem cell (hPSC)-derived RPE cells has emerged as a potential therapy for retinal degeneration. However, RPE cells differentiated from hPSCs using current protocols are xeno-containing and are rarely applied in clinical trials. The development of hPSC-derived RPE cell differentiation protocols using xeno-free biomaterials is urgently needed for clinical applications. In this study, two protocols (the activin A and NIC84 protocols) were selected for modification and use in the differentiation of hiPSCs into RPE cells; the chetomin concentration was gradually increased to achieve high differentiation efficiency of RPE cells. The xeno-free extracellular matrix (ECM) proteins, laminin-511, laminin-521 and recombinant vitronectin, were selected as plate-coating substrates, and a Matrigel (xeno-containing ECM)-coated surface was used as a positive control. Healthy, mature hPSC-derived RPE cells were transplanted into 21-day-old Royal College of Surgeons (RCS) rats, a model of retinal degeneration disease. The visual function of RCS rats was evaluated by optomotor response (qOMR) and electroretinography after transplantation of hPSC-derived RPE cells. Our study demonstrated that hPSCs can be efficiently differentiated into RPE cells on LN521-coated dishes using the NIC84 protocol, and that subretinal transplantation of the cell suspensions can delay the progression of vision loss in RCS rats.

Gadolinium Leakage into Ocular Structures (GLOS) is common following acute cerebrovascular events. The objective of this study was to investigate the occurrence of GLOS in an acute traumatic brain injury (TBI) cohort without acute cerebrovascular injury and to explore associated factors.

Enrolled acute TBI patients had a baseline MRI ≤48 h of injury (TP1) and follow-up MRI ≤72 h after baseline (TP2). Vitreous chamber enhancement and signal intensity ratios (SIRs) were calculated using pre- and post-contrast Fluid Attenuated Inversion Recovery (FLAIR). White matter hyperintensities (WMHs) were assessed using the Fazekas scale.

Of the 128 TBI patients included, median age was 47 years, 70% male, and 66% presented with Glasgow Coma Scale of 15. No GLOS was detected at TP1 but was present in 23% of patients at TP2. GLOS+ patients were older (68 years [56-76] vs 39 years [27-53], p < 0.001), more likely to report falls as injury mechanism (62% vs 36%, p = 0.006), report history of hypertension (41% vs 19%, p = 0.025), and had a higher burden of WMHs (59% vs 14% with a total Fazekas ≥2, p < 0.001). Quantitative SIRs confirmed qualitative assessments: GLOS+ patients had higher SIRs at TP2 (0.43 vs 0.22, p < 0.001). Age (OR 3.28, 95%CI [1.88-5.71], p < 0.001) and prior TBI history (OR 4.99, 95%CI [1.46-17.06], p = 0.010) were independent predictors of GLOS. When age was removed, total Fazekas score (OR 2.53, 95%CI [1.60-4.00], p < 0.001) was an independent predictor of GLOS.

GLOS is primarily associated with age and may serve as another imaging marker of chronic vascular disease.

The retina's similar structure and function to the brain make it a unique visual "window" for studying cerebral disorders. Ophthalmic artery occlusion (OAO) or retinal artery occlusion (RAO) is a severe ophthalmic emergency that significantly affects visual acuity. Studies have demonstrated that patients with OAO or RAO face a notably higher risk of future acute ischemic stroke (AIS). However, ophthalmologists often overlook multidisciplinary approach involving the neurologist, to evaluate the risk of AIS and devise clinical treatment strategies for patients with OAO or RAO. Unlike the successful use of thrombolysis in AIS, the application of thrombolysis for OAO or RAO remains limited and controversial due to insufficient reliable evidence. In this review, we aim to summarize the anatomical and functional connections between the retina and the brain, and the clinical connection between OAO or RAO and AIS, compare and review recent advances in the effectiveness and safety of intravenous and intra-arterial thrombolysis therapy in patients with OAO or RAO, and discuss future research directions for OAO or RAO. Our goal is to advance the development of multidisciplinary diagnosis and treatment strategies for the disease, as well as to establish expedited pathways or thrombolysis guidelines for vascular intervention.

This study aims to reveal the immunopathogenesis of the high-risk corneal transplantation using a comparative proteomic approach.

The immunological properties of ocular tissues (including corneal grafts, aqueous humour, and iris-ciliary body) were analysed using a high-risk rabbit corneal transplantation model employing a comparative proteomic approach.

The corneal grafts revealed a dramatic increase in the immune response both at the early (postoperative day 7) and rejection stages, along with the appearance of transplantation stress-induced cellular senescence in the early stage. The aqueous humour (AH) displayed persistent pathological alterations, indicated by the significant enrichment of complement and coagulation cascades pathway in the early stage and interleukin (IL)-17 signalling pathway in the rejection stage. More surprisingly, the pronounced elevation of immune response was also observed in the iris-ciliary body (I-CB) tissues at the early and rejection stages. The enriched immune-related pathways were associated with antigen processing and presentation, complement and coagulation cascades, and IL-17 signalling pathway. Furthermore, proteomic analysis revealed that the implantation of Cyclosporine A drug delivery system (CsA-DDS) into the anterior chamber obviously mitigated corneal transplantation rejection by inhibiting immunoreaction both in the corneal grafts and I-CB tissues.

The results highlighted the involvement of intraocular immunity both in the grafts and I-CB tissues during corneal transplantation rejection, further suggesting the anterior chamber as an optimal drug-delivery site for its treatment.

Autism spectrum disorder (ASD) is a widely recognized neurodevelopmental disorder, yet the identification of reliable imaging biomarkers for its early diagnosis remains a challenge. Considering the specific manifestations of ASD in the eyes and the interconnectivity between the brain and the eyes, this study investigates ASD through the lens of retinal analysis. We specifically examined differences in the macular region of the retina using optical coherence tomography (OCT)/optical coherence tomography angiography (OCTA) images between children diagnosed with ASD and those with typical development (TD). Our findings present potential novel characteristics of ASD: the thickness of the ellipsoid zone (EZ) with cone photoreceptors was significantly increased in ASD; the large-caliber arteriovenous of the inner retina was significantly reduced in ASD; these changes in the EZ and arteriovenous were more significant in the left eye than in the right eye. These observations of photoreceptor alterations, vascular function changes, and lateralization phenomena in ASD warrant further investigation, and we hope that this work can advance interdisciplinary understanding of ASD.

The impact of plastic pollution on living organisms have gained significant research attention. However, the effects of nanoplastics (NPs) on retina remain unclear. This study aimed to investigate the effect of long-term polystyrene nanoparticles (PS-NPs) exposure on mouse retina. Eight weeks old C57BL/6 J mice were exposed to PS-NPs at the diameter of 100 nm and concentration of 10 mg/L in drinking water for 3 months. PS-NPs were able to penetrate the blood-retina barrier, accumulated at retinal tissue, caused increased oxidative stress level and reduced scotopic electroretinal responses without remarkable structural damage. PS-NPs exposure caused cytotoxicity and reactive oxygen species accumulation in cultured photoreceptor cell. PS-NPs exposure increased oxidative stress level in retinal pigment epithelial (RPE) cells, leading to changes of gene and protein expression indicative of compromised phagocytic activity and cell junction formation. Long-term PS-NPs exposure also aggravated light-induced photoreceptor cell degeneration and retinal inflammation. The transcriptomic profile of PS-NPs-exposed, light-challenged retinal tissue shared similar features with those of age-related macular degeneration (AMD) patients in the activation of complement-mediated phagocytic and proinflammatory responses. Collectively, these findings demonstrated the oxidative stress- and inflammation-mediated detrimental effect of PS-NPs on retinal function, suggested that long-term PS-NPs exposure could be an environmental risk factor contributing to retinal degeneration.

The anterior chamber of the eye (ACE) is distinct in its anatomy, optics, and immunology. This guarantees that the eye perceives visual information in the context of physiology even when encountering adverse incidents like inflammation. In addition, this endows the ACE with the special nursery bed iris enriched in vasculatures and nerves. The ACE constitutes a confined space enclosing an oxygen/nutrient-rich, immune-privileged, and less stressful milieu as well as an optically transparent medium. Therefore, aside from visual perception, the ACE unexpectedly serves as an excellent transplantation site for different body parts and a unique platform for noninvasive, longitudinal, and intravital microimaging of different grafts. On the basis of these merits, the ACE technology has evolved from the prototypical through the conventional to the advanced version. Studies using this technology as a versatile biomedical research platform have led to a diverse range of basic knowledge and in-depth understanding of a variety of cells, tissues, and organs as well as artificial biomaterials, pharmaceuticals, and abiotic substances. Remarkably, the technology turns in vivo dynamic imaging of the morphological characteristics, organotypic features, developmental fates, and specific functions of intracameral grafts into reality under physiological and pathological conditions. Here we review the anatomical, optical, and immunological bases as well as technical details of the ACE technology. Moreover, we discuss major achievements obtained and potential prospective avenues for this technology.

Whole-eye transplantation emerges as a frontier in ophthalmology, promising a transformative approach to irreversible blindness. Despite advancements, formidable challenges persist. Preservation of donor eye viability post-enucleation necessitates meticulous surgical techniques to optimize retinal integrity and ganglion cell survival. Overcoming the inhibitory milieu of the central nervous system for successful optic nerve regeneration remains elusive, prompting the exploration of neurotrophic support and immunomodulatory interventions. Immunological tolerance, paramount for graft acceptance, confronts the distinctive immunogenicity of ocular tissues, driving research into targeted immunosuppression strategies. Ethical and legal considerations underscore the necessity for stringent standards and ethical frameworks. Interdisciplinary collaboration and ongoing research endeavors are imperative to navigate these complexities. Biomaterials, stem cell therapies, and precision immunomodulation represent promising avenues in this pursuit. Ultimately, the aim of this review is to critically assess the current landscape of whole-eye transplantation, elucidating the challenges and advancements while delineating future directions for research and clinical practice. Through concerted efforts, whole-eye transplantation stands to revolutionize ophthalmic care, offering hope for restored vision and enhanced quality of life for those afflicted with blindness.

Background: To systematically review and meta-analyze the immunologic aspects and outcomes of various endothelial keratoplasty (EK) techniques, specifically comparing Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK), Ultra-Thin Descemet's Stripping Automated Endothelial Keratoplasty (UT-DSAEK), and Descemet's Membrane Endothelial Keratoplasty (DMEK). Methods: Systematic review and meta-analysis. Main outcomes were the proportion of patients achieving a best spectacle-corrected visual acuity (BSCVA) of 20/20 at 6 months after keratoplasty, rejection rate one year after surgery, BSCVA at last follow up, and postoperative immunomodulating regimen. Results: A higher proportion of DMEK patients achieved a BSCVA of 20/20 after 6 months. UT-DSAEK and DMEK showed similar rejection rates with a lower risk of re-bubbling for UT-DSAEK (4% vs. 20%). Conclusions: DMEK showed faster visual recovery than UT-DSAEK but a similar rejection rate and long-term visual acuity. One-year postoperative slow tapering steroid regimen has a positive but not (yet) significant effect on rejection risk and visual outcomes.

Molecular optogenetics utilizes genetically encoded, light-responsive protein switches to control the function of molecular processes. Over the last two years, there have been notable advances in the development of novel optogenetic switches, their utilization in elucidating intricate signaling pathways, and their progress toward practical applications in biotechnological processes, material sciences, and therapeutic applications. In this review, we discuss these areas, offer insights into recent developments, and contemplate future directions.

Medical microrobotics is an emerging field to revolutionize clinical applications in diagnostics and therapeutics of various diseases. On the other hand, the mobile microrobotics field has important obstacles to pass before clinical translation. This article focuses on these challenges and provides a roadmap of medical microrobots to enable their clinical use. From the concept of a "magic bullet" to the physicochemical interactions of microrobots in complex biological environments in medical applications, there are several translational steps to consider. Clinical translation of mobile microrobots is only possible with a close collaboration between clinical experts and microrobotics researchers to address the technical challenges in microfabrication, safety, and imaging. The clinical application potential can be materialized by designing microrobots that can solve the current main challenges, such as actuation limitations, material stability, and imaging constraints. The strengths and weaknesses of the current progress in the microrobotics field are discussed and a roadmap for their clinical applications in the near future is outlined.

Virus-like particles (VLP) are a promising tool for intracellular gene delivery, yet their potential in ocular gene therapy remains underexplored. In this study, we bridged this knowledge gap by demonstrating the successful generation and application of vesicular stomatitis virus glycoprotein (VSVG)-pseudotyped mouse PEG10 (MmPEG10)-VLP for intraocular mRNA delivery. Our findings revealed that PEG10-VLP can efficiently deliver GFP mRNA to adult retinal pigment epithelial cell line-19 (ARPE-19) cells, leading to transient expression. Moreover, we showed that MmPEG10-VLP can transfer SMAD7 to inhibit epithelial-mesenchymal transition (EMT) in RPE cells effectively. In vivo experiments further substantiated the potential of these vectors, as subretinal delivery into adult mice resulted in efficient transduction of retinal pigment epithelial (RPE) cells and GFP reporter gene expression without significant immune response. However, intravitreal injection did not yield efficient ocular expression. We also evaluated the transduction characteristics of MmPEG10-VLP following intracameral delivery, revealing transient GFP protein expression in corneal endothelial cells without significant immunotoxicities. In summary, our study established that VSVG pseudotyped MmPEG10-based VLP can transduce mitotically inactive RPE cells and corneal endothelial cells in vivo without triggering an inflammatory response, underscoring their potential utility in ocular gene therapy.

To describe the reversal of peripheral iris depigmentation associated with Vogt-Koyanagi-Harada (VKH) disease.

A retrospective report of two cases.

Both patients were diagnosed with a chronic recurrent VKH disease and developed bilateral peripheral iris depigmentation (BPID). The first patient is an 8-year-old girl who was treated with systemic corticosteroids, methotrexate and adjuvant rituximab infusions that induced complete remission of uveitis and reversal of peripheral iris depigmentation at the last follow-up. The second was a 6-year-old who was treated with topical and systemic corticosteroids and oral methotrexate that induced complete remission of uveitis and reversal of peripheral iris depigmentation at the last follow-up.

Adequate control of uveitis associated with chronic recurrent VKH disease with appropriate immunomodulatory agents and perhaps adjuvant rituximab can reverse BPID and improve the outcomes.