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Single-cell RNA sequencing (scRNA-seq) has enabled the identification of novel gene signatures and cell heterogeneity in numerous tissues and diseases. Here we review the use of this technology for Fuchs' Endothelial Corneal Dystrophy (FECD). FECD is the most common indication for corneal endothelial transplantation worldwide. FECD is challenging to manage because it is genetically heterogenous, can be autosomal dominant or sporadic, and progress at different rates. Single-cell RNA sequencing has enabled the discovery of several FECD subtypes, each with associated gene signatures, and cell heterogeneity. Current FECD treatments are mainly surgical, with various Rho kinase (ROCK) inhibitors used to promote endothelial cell metabolism and proliferation following surgery. A range of emerging therapies for FECD including cell therapies, gene therapies, tissue engineered scaffolds, and pharmaceuticals are in preclinical and clinical trials. Unlike conventional disease management methods based on clinical presentations and family history, targeting FECD using scRNA-seq based precision-medicine has the potential to pinpoint the disease subtypes, mechanisms, stages, severities, and help clinicians in making the best decision for surgeries and the applications of therapeutics. In this review, we first discuss the feasibility and potential of using scRNA-seq in clinical diagnostics for FECD, highlight advances from the latest clinical treatments and emerging therapies for FECD, integrate scRNA-seq results and clinical notes from our FECD patients and discuss the potential of applying alternative therapies to manage these cases clinically., Competing Interests: Conflict of interest The authors have no conflicts of interest to disclose., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Purpose: The present review will summarize FECD-associated genes and pathophysiology, diagnosis, current  therapeutic approaches, and future treatment perspectives., Methods: Literature review., Results: Fuchs' endothelial corneal dystrophy (FECD) is the most common bilateral corneal dystrophy and accounts for one-third of all corneal transplants performed in the US. FECD is caused by a combination of genetic and non-heritable factors, and there are two types: early-onset FECD, which affects individuals from an early age and is usually more severe, and late-onset FECD, which is more common and typically manifests around the age of 40. The hallmark findings of FECD include progressive loss of corneal endothelial cells and the formation of focal excrescences (guttae) on the Descemet membrane. These pathophysiological changes result in progressive endothelial dysfunction, leading to a decrease in visual acuity and blindness in later stages. The present review will summarize FECD-associated genes and pathophysiology, diagnosis, current therapeutic approaches, and future treatment perspectives., Conclusion: With the characterization and understanding of FECD-related genes and ongoing research into regenerative therapies for corneal endothelium, we can hope to see more significant improvements in the future in the management and care of the disease., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Purpose: Endothelial keratoplasty (EK) is the conventional treatment to improve visual acuity of corneal endothelium decompensation (CED) patients, with other therapies mainly for symptomatic relief. However, the shortage of corneal grafts and other limitations to EK urge the development of novel alternative treatments. In the last decade, novel options have been proposed, yet only a limited number of reviews have systematically reported on outcomes. Therefore, this systematic review evaluates the existing clinical evidence of novel surgical approaches for CED., Method: We identified 24 studies that illustrated the clinical observations of the surgical approaches in interest. We included Descemet stripping only (DSO), Descemet membrane transplantation (DMT) where Descement membrane alone instead of corneal endothelium with cells is transplanted, and cell-based therapy., Results: In general, these therapies may provide visual outcomes comparable with EK under specific conditions. DSO and DMT target CED with relatively healthy peripheral corneal endothelium like Fuchs' corneal endothelial dystrophy, while cell-based therapy offers more versatile applications. Side effects of DSO would decrease with modifications to surgical techniques. Moreover, Rho-associated protein kinase inhibitor adjuvant therapy could enhance clinical results in DSO and cell-based therapy., Conclusion: Long-term controlled clinical trials with larger sample size on the therapies are needed. The simplicity of DSO and the high translational potential of cell-based therapy to treat CED of most etiologies made these two treatment strategies promising., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Abstract: Corneal tomography has an emerging role in the assessment of Fuchs endothelial corneal dystrophy (FECD) in clinical practice and potentially for future clinical trials. Posterior elevation and pachymetry maps derived from elevation based Scheimpflug tomography can detect early corneal edema, even at a subclinical stage, enabling clinicians to better counsel patients about their vision and the risk of disease progression with and without cataract surgery. Tomographic imaging provides a functional assessment of corneal endothelial health, and could enable objective assessment of FECD progression, or regression, in response to novel therapeutic interventions. Clinicians and investigators should adopt Scheimpflug imaging for the assessment of FECD over traditional morphologic imaging modalities., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Current treatment for corneal endothelial dysfunction consists in the replacement of corneal endothelium by keratoplasty. Owing to the scarcity of donor corneas and the increasing number of transplants, alternative treatments such as cell-based therapies are necessary. In this article, we highlight the biological aspects of the cornea and the corneal endothelium, as well as the context that surrounds the need for new alternatives to conventional keratoplasty. We then review some of those experimental treatments in more detail, focusing on the development of the in vitro and preclinical phases of two cell-based therapies: tissue-engineered endothelial keratoplasty (TE-EK) and cell injection. In the case of TE-EK graft construction, we analyse the current progress, considering all the requirements it must meet in order to be functional. Moreover, we discuss the inherent drawbacks of endothelial keratoplasties, which TE-EK grafts should overcome in order to make surgical intervention easier and to improve the outcomes of current endothelial keratoplasties. Finally, we analyse the development of preclinical trials and their limitations in terms of performing an optimal functional evaluation of cell-based therapy, and we conclude by discussing early clinical trials in humans., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose: To report the safety and efficacy of a novel cell injection therapy using cultured human corneal endothelial cells (hCECs) for endothelial failure conditions via the report of the long-term 5-year postoperative clinical data from a first-in-humans clinical trial group., Design: Prospective observational study., Participants: This study involved 11 eyes of 11 patients with pseudophakic endothelial failure conditions who underwent hCEC injection therapy between December 2013 and December 2014., Methods: All patients underwent follow-up examinations at 1 week, 4 weeks, 12 weeks, and 24 weeks and 1 year, 2 years, 3 years, 4 years, and 5 years after surgery. Specific corneal endothelial cell parameters (i.e., corneal endothelial cell density [ECD], coefficient of variation of area, and percentage of hexagonal cells) and central corneal thickness, best-corrected visual acuity (BCVA) on a Landolt C eye chart, and intraocular pressure (IOP) were recorded., Main Outcome Measures: The primary outcome was the change in central ECD after cell injection therapy, and the secondary outcome was corneal thickness, BCVA, and IOP during the 5-year-postoperative follow-up period., Results: At 5 years after surgery, normal corneal endothelial function was restored in 10 of the 11 eyes, the mean ± standard deviation central corneal ECD was 1257 ± 467 cells/mm 2 (range, 601-2067 cells/mm 2 ), BCVA improved significantly in 10 treated eyes, the mean visual acuity changed from 0.876 logarithm of the minimum angle of resolution before surgery to 0.046 logarithm of the minimum angle of resolution after surgery, and no major adverse reactions directly related to the hCEC injection therapy were observed., Conclusions: The findings in this study confirmed the safety and efficacy of cultured hCEC injection therapy for up to 5 years after surgery., (Copyright © 2020 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

The cornea is a multi-layered structure which allows fine refraction and provides both resistance to external insults and adequate transparency. The corneal endothelium ensures stromal hydration, failure of which, such as in Fuchs endothelial corneal dystrophy, after trauma or in aging, may lead to loss of corneal transparency and induce blindness. Currently, no efficient therapeutic alternatives exist except for corneal grafting. Thus corneal tissue engineering represents a valuable alternative approach, which may overcome cornea donor shortage. Several studies describe protocols to isolate, differentiate, and cultivate corneal endothelial cells (CEnCs) in vitro. Two main in vitro strategies can be described: expansion of eye-native cell populations, such as CEnCs, or the production and expansion of CEnCs from non-eye native cell populations, such as induced Pluripotent Stem Cells (iPSCs). The challenge with these cells is to obtain a monolayer of CEnCs on a biocompatible carrier, with a specific morphology (flat hexagonal cells), and with specific functions such as programmed cell cycle arrest. Another issue for this cell culture methodology is to define the adapted protocol (media, trophic factors, timeframe) that can mimic physiological development. Additionally, contamination by other cell types still represents a huge problem. Thus, purification methods, such as Fluorescence Activated Cell Sorting (FACS), Magnetic Ativated Cell Sorting (MACS) or Sedimentation Field Flow Fractionation (SdFFF) are useful. Animal models are also crucial to provide a translational approach for these therapies, integrating macro- and microenvironment influences, systemic hormonal or immune responses, and exogenous interactions. Non-eye native cell graft protocols are constantly improving both in efficacy and safety, with the aim of being the most suitable candidate for corneal therapies in future routine practice. The aim of this work is to review these different aspects with a special focus on issues facing CEnC culture in vitro, and to highlight animal graft models adapted to screen the efficacy of these different protocols., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose: To report early safety and efficacy of Descemet stripping only (DSO) supplemented with ripasudil., Methods: A pre-post clinical trial with a historical control group for time to heal and cell count parameters. The study received ethics approval and was conducted with oversight of a data safety monitoring board. All enrolled patients had a superior endothelial cell count of >1000 cells/mm2 and were symptomatic from the presence of central guttata degrading vision and/or producing glare. DSO was carried out with a peeling technique and not combined with any other intervention. Ripasudil 0.4% was applied topically from day 1 postoperatively at a dose of 6 times/d until corneal clearance. Cases with relapse of edema were permitted to restart on ripasudil at a reduced dose of 2 drops/d for a further 2 weeks. Stopping rules with progression to a corneal graft were established. Baseline ocular and systemic investigations were carried out and repeated at varying intervals to monitor for local and systemic adverse events., Results: Twenty-three eyes of 23 patients met the inclusion criteria and underwent DSO. Twenty-two of 23 eyes achieved corneal clearance at a mean time of 4.1 weeks. In all patients achieving clearance, improvement in vision was recorded. Improvement in mean uncorrected visual acuity was 0.20 Logarithm of the minimum angle of resolution (LogMar), and improvement in mean best spectacle corrected visual acuity was 0.156 LogMar. One patient failed to clear and underwent Descemet membrane endothelial keratoplasty at week 12. Twenty-one of 22 patients achieving corneal clearance expressed satisfaction with the procedure. The commonest systemic side effect of topical ripasudil was gastrointestinal upset (24%), and the commonest local side effect was ocular irritation (43%). No patient experienced a serious adverse event in the course of the trial. Thirty-nine percent of patients experienced a relapse of edema on ceasing ripasudil, with clearance again on recommencing., Conclusions: This trial of DSO supplemented with ripasudil included local and systemic safety analysis. We judge that this treatment option is emerging as a reliable intervention for select patients with Fuchs' Endothelial Corneal Dystrophy (FECD) with an acceptable safety profile. The observation of relapse edema is strong evidence of a drug effect. The longevity of these results remains unknown., Competing Interests: G. Moloney is a consultant for Kowa Ind. manufacturers of Glanatec (ripasudil). N. Hirnschall is a scientific consultant for HOYA Surgical and Carl Zeiss Meditec AG. The remaining authors have no conflicts of interest to disclose., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Antisense oligonucleotides (ASOs) are synthetic nucleic acids that recognize complementary RNA sequences inside cells and modulate gene expression. In this study, we explore the feasibility of ASO delivery to the cornea. We used quantitative polymerase chain reaction to test the efficacy of a benchmark ASO targeting a noncoding nuclear RNA, Metastasis-Associated Lung Adenocarcinoma Transcript 1 ( MALAT1 ), in a human corneal endothelial cell line, ex vivo human corneas, and in vivo in mice. In vivo delivery was via intravitreal or intracameral injections as well as topical administration. The anti- MALAT1 ASO significantly reduced expression of MALAT1 in a corneal endothelial cell line. We achieved a dose-dependent reduction of target gene expression in endothelial tissue from ex vivo human donor corneas. In vivo mouse experiments confirmed MALAT1 reduction in whole corneal tissue via intravitreal and intracameral routes, 82% and 71% knockdown, respectively ( P  < 0.001). Effects persisted up to at least 21 days, 32% ( P  < 0.05) and 43% ( P  < 0.05) knockdown, respectively. We developed protocols for the isolation and analysis of mouse corneal endothelium and observed reduction in MALAT1 expression upon both intravitreal and intracameral administrations, 64% ( P  < 0.05) and 63% ( P  < 0.05) knockdown, respectively. These data open the possibility of using ASOs to treat corneal disease.

How genetic defects trigger the molecular changes that cause late-onset disease is important for understanding disease progression and therapeutic development. Fuchs' endothelial corneal dystrophy (FECD) is an RNA-mediated disease caused by a trinucleotide CTG expansion in an intron within the TCF4 gene. The mutant intronic CUG RNA is present at one-two copies per cell, posing a challenge to understand how a rare RNA can cause disease. Late-onset FECD is a uniquely advantageous model for studying how RNA triggers disease because: (i) Affected tissue is routinely removed during surgery; (ii) The expanded CTG mutation is one of the most prevalent disease-causing mutations, making it possible to obtain pre-symptomatic tissue from eye bank donors to probe how gene expression changes precede disease; and (iii) The affected tissue is a homogeneous single cell monolayer, facilitating accurate transcriptome analysis. Here, we use RNA sequencing (RNAseq) to compare tissue from individuals who are pre-symptomatic (Pre&#95;S) to tissue from patients with late stage FECD (FECD&#95;REP). The abundance of mutant repeat intronic RNA in Pre&#95;S and FECD&#95;REP tissue is elevated due to increased half-life in a corneal cells. In Pre&#95;S tissue, changes in splicing and extracellular matrix gene expression foreshadow the changes observed in advanced disease and predict the activation of the fibrosis pathway and immune system seen in late-stage patients. The absolute magnitude of splicing changes is similar in pre-symptomatic and late stage tissue. Our data identify gene candidates for early drivers of disease and biomarkers that may represent diagnostic and therapeutic targets for FECD. We conclude that changes in alternative splicing and gene expression are observable decades prior to the diagnosis of late-onset trinucleotide repeat disease., (© The Author(s) 2020. Published by Oxford University Press on behalf of Nucleic Acids Research.)

Rationale: Mitochondrial disorders preferentially affect tissues with high energy requirements, such as the retina and corneal endothelium, in human eyes. Mesenchymal stem cell (MSC)-based treatment has been demonstrated to be beneficial for ocular degeneration. However, aside from neuroprotective paracrine actions, the mechanisms underlying the beneficial effect of MSCs on retinal and corneal tissues are largely unknown. In this study, we investigated the fate and associated characteristics of mitochondria subjected to intercellular transfer from MSCs to ocular cells. Methods: MSCs were cocultured with corneal endothelial cells (CECs), 661W cells (a photoreceptor cell line) and ARPE-19 cells (a retinal pigment epithelium cell line). Immunofluorescence, fluorescence activated cell sorting and confocal microscopy imaging were employed to investigate the traits of intercellular mitochondrial transfer and the fate of transferred mitochondria. The oxygen consumption rate of recipient cells was measured to investigate the effect of intercellular mitochondrial transfer. Transcriptome analysis was performed to investigate the expression of metabolic genes in recipient cells with donated mitochondria. Results: Mitochondrial transport is a ubiquitous intercellular mechanism between MSCs and various ocular cells, including the corneal endothelium, retinal pigmented epithelium, and photoreceptors. Additionally, our results indicate that the donation process depends on F-actin-based tunneling nanotubes. Rotenone-pretreated cells that received mitochondria from MSCs displayed increased aerobic capacity and upregulation of mitochondrial genes. Furthermore, living imaging determined the ultimate fate of transferred mitochondria through either degradation by lysosomes or exocytosis as extracellular vesicles. Conclusions: For the first time, we determined the characteristics and fate of mitochondria undergoing intercellular transfer from MSCs to various ocular cells through F-actin-based tunneling nanotubes, helping to characterize MSC-based treatment for ocular tissue regeneration., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

The human corneal endothelium (CE) is a post-mitotic monolayer of endothelial cells, thought to be incapable of in vivo regeneration. Dysfunction of the CE is a commonly cited indication for corneal transplantation, with corneal blindness being the fifth most common cause of blindness globally. In 2012 alone 184,576 corneal transplants were performed in 116 countries (Gain et al., 2016). Presently, outcomes following human corneal transplantation have been reported to have over 97% success rate in restoring the recipient's vision (Patel et al., 2019). However, the continuing demand for cadaveric human corneas has driven research into alternative sources of CE and with the advent of protocols to produce cultured hCECs there is now the potential for cell therapy to regenerate the damaged CE. This review aims to examine the merits and limitations of different types of human and animal models used so far to test the concept of CE cell therapy., (Crown Copyright © 2019. Published by Elsevier Ltd. All rights reserved.)

Fuchs' endothelial corneal dystrophy (FECD) is the most prominent reason for corneal-endothelial transplantations across the globe. The disease pathophysiology manifests through a combination of various genetic and non-heritable factors. This review provides a comprehensive list of known genetic players that cause FECD, and discusses the prominent pathological features that participate in disease progression, such as channel dysfunction, abnormal extracellular matrix deposition, RNA toxicity, oxidative stress, and apoptosis. Although current practices to correct visual acuity involve surgical intervention, this review also discusses the scope of various non-surgical therapeutics to remedy FECD.

Fuchs' endothelial corneal dystrophy (FECD) leads to vision loss and is one of the most common inherited eye diseases. Corneal transplants are the only curative treatment available, and there is a major unmet need for treatments that are less invasive and independent of donor tissue. Most cases of FECD are associated with an expanded CUG repeat within the intronic region of TCF4 and the mutant RNA has been implicated as the cause of the disease. We previously presented preliminary data suggesting that single-stranded antisense oligonucleotides (ASOs) can inhibit CUG RNA foci in patient-derived cells and tissue. We now show that duplex RNAs and single-stranded silencing RNAs (ss-siRNAs) reduce the number of cells with foci and the number of foci per cells. Potencies are similar to those that are achieved with chemically modified ASOs designed to block foci. These data widen the potential for synthetic nucleic acids to be used to treat a widely prevalent and debilitating disease.

Purpose: To assess the morphological and functional outcomes of Descemet membrane endothelial keratoplasty (DMEK) performed with pre-stripped tissue preserved in organ culture medium containing dextran compared to tissue preserved in dextran-free medium., Methods: In this retrospective study, we reviewed the clinical records of 103 patients who underwent DMEK surgery with pre-stripped tissue in our department between June 2015 and September 2016. The endothelium-Descemet membrane layer was preserved in organ culture medium for a maximum of 48 h for all patients. For group 1, 49 endothelium-Descemet membrane (EDM) were stripped and preserved in medium 1 (dextran-free organ culture medium), while 54 EDM were stripped and preserved in medium 2 (organ culture medium supplemented with 6% dextran T-500) for group 2. Outcome measures included best-corrected visual acuity (BCVA), central corneal thickness (CCT), and endothelial cell density (ECD) of all eyes in both groups at three consecutive postoperative time points: 2 weeks, 6 weeks, and 6 months postoperatively. We also compared the repeat keratoplasty rates between the groups., Results: Group 1 showed a statistically significant better BCVA compared to group 2 at each time point (p < 0.05). The percentage of grafts achieving 0.5 or better after 6 months in group 1 was 96% and in group 2, it was 66% (P < 0.001). CCT was significantly lower in group 1 compared to group 2 at 2 weeks and 6 months after surgery (p < 0.05). ECD was comparable between donor grafts before surgery but was significantly greater in groups 1 after 2 and 6 weeks (p < 0.05), but not after 6 months. Necessity for repeat keratoplasty (repeat DMEK, subsequent penetrating keratoplasty (PKP)) was significantly lower in group 1 (p < 0.05)., Conclusions: Pre-stripped tissue for DMEK preserved in dextran-free medium led to better visual recovery, thinner postoperative corneas, a higher endothelial cell density, and a lower rate of repeat keratoplasty, indicating that dextran has an unfavorable impact on the preservation of pre-stripped DMEK tissue.

Objective: Comparison of conventional Penetrating Keratoplasty (PKP), posterior mushroom PKP and Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK) regarding overall graft survival of primary corneal transplants for Fuchs´ endothelial dystrophy (FED), best spectacle-corrected visual acuity (BSCVA) and astigmatism., Methods: Single centre study using prospectively collected data from the national database for follow-up of corneal transplants. Main outcome parameters: 10 years graft survival, astigmatism at 24 months, pre- and post-operative BSCVA., Results: In total, 721 cases were included: PKP, n = 171; posterior mushroom PKP, n = 91; and DSAEK, n = 459. There was no significant difference in graft survival between PKP, posterior mushroom PKP and the DSAEK technique (log-rank test, P = 0.12). The overall post-operative BSCVA improvement in all treatment groups was significant (paired t-test, P<0.001). Pre-operative BSCVA was better for the DSAEK group (0.68 ± 0.41 logMAR) as compared to the PKP (0.89 ± 0.53) and posterior mushroom PKP group (0.90 ± 0.58); ANOVA, P<0.001. After 24 months, BSCVA was significantly better for the DSAEK group (0.25 ± 0.26 logMAR) compared to the PKP (0.35 ± 0.29) and posterior mushroom PKP group (0.41 ± 0.42); ANOVA, P<0.001. A significant difference in astigmatism was found (median test, P<0.001) between the DSAEK (1.7 ± 1.1 D), PKP (4.6 ± 2.7 D) and posterior mushroom PKP group (4.5 ± 3.3 D). The significantly lower DSAEK-induced astigmatism was confirmed by vector analysis., Conclusion: There was no difference in graft survival and BSCVA improvement between conventional PKP, inverted mushroom PKP and DSAEK in this study. The significantly lower changes in astigmatism, wound stability and faster visual rehabilitation with DSAEK surgery are favourable aspects of this technique. The benefits of posterior lamellar keratoplasty warrant earlier intervention, which may contribute to preserve better vision for a prolonged period of remaining lifetime., Competing Interests: The authors have declared that no competing interests exist.

Unraveling the genetic mechanisms of Fuchs endothelial corneal dystrophy has opened new possibilities for future targeted medical therapy of the disease. Until these possibilities mature, regenerative semi-surgical approaches by cell injection or cell sheet transfer could help expand the donor pool, and possibly enable autologous transplantation. Descemet membrane stripping alone and acellular Descemet membrane transfer are more immediate surgical approaches that could be temporary treatments in some patients, though there is a lack of understanding of the factors that predict success for these procedures. Regardless of approach, clinical trials will be necessary, and clinicians should therefore try to standardize their methods of assessing disease severity and the outcomes of intervention., Competing Interests: The authors declare no conflict of interest., (Georg Thieme Verlag KG Stuttgart · New York.)

Fuchs endothelial corneal dystrophy (FECD) is a genetic and oxidative stress disorder of post-mitotic human corneal endothelial cells (HCEnCs), which normally exhibit hexagonal shape and form a compact monolayer compatible with normal corneal functioning and clear vision. FECD is associated with increased DNA damage, which in turn leads to HCEnC loss, resulting in the formation rosettes and aberrant extracellular matrix (ECM) deposition in the form of pro-fibrotic guttae. Since the mechanism of ECM deposition in FECD is currently unknown, we aimed to investigate the role of endothelial-mesenchymal transition (EMT) in FECD using a previously established cellular in vitro model that recapitulates the characteristic rosette formation, by employing menadione (MN)-induced oxidative stress. We demonstrate that MN treatment alone, or a combination of MN and TGF-β1 induces reactive oxygen species (ROS), cell death, and EMT in HCEnCs during rosette formation, resulting in upregulation of EMT- and FECD-associated markers such as Snail1, N-cadherin, ZEB1, and transforming growth factor-beta-induced (TGFβI), respectively. Additionally, FECD ex vivo specimens displayed a loss of organized junctional staining of plasma membrane-bound N-cadherin, with corresponding increase in fibronectin and Snail1 compared to ex vivo controls. Addition of N-acetylcysteine (NAC) downregulated all EMT markers and abolished rosette formation. Loss of NQO1, a metabolizing enzyme of MN, led to greater increase in intracellular ROS levels as well as a significant upregulation of Snail1, fibronectin, and N-cadherin compared to normal cells, indicating that NQO1 regulates Snail1-mediated EMT. This study provides first line evidence that MN-induced oxidative stress leads to EMT in corneal endothelial cells, and the effect of which is further potentiated when redox cycling activity of MN is enhanced by the absence of NQO1. Given that NAC inhibits Snail-mediated EMT, this may be a potential therapeutic intervention for FECD., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Corneal transparency is maintained by the corneal endothelium through its pump and barrier function. Severe corneal endothelial damage results in dysregulation of water flow and eventually causes corneal haziness and deterioration of visual function. In 2013, we initiated clinical research of cell-based therapy for treating corneal decompensation. In that study, we removed an 8-mm diameter section of damaged corneal endothelium without removing Descemet's membrane (the basement membrane of the corneal endothelium) and then injected cultured human corneal endothelial cells (CECs) into the anterior chamber. However, Descemet's membrane exhibits clinically abnormal structural features [i.e., multiple collagenous excrescences (guttae) and thickening] in patients with Fuchs endothelial corneal dystrophy (FECD) and the advanced cornea guttae adversely affects the quality of vision, even in patients without corneal edema. The turnover time of cornea guttae is also not certain. Therefore, we used a rabbit model to evaluate the feasibility of Descemet's membrane removal in the optical zone only, by performing a small 4-mm diameter descemetorhexis prior to CEC injection. We showed that the corneal endothelium is regenerated both on the corneal stroma (the area of Descemet's membrane removal) and on the intact peripheral Descemet's membrane, based on the expression of function-related markers and the restoration of corneal transparency. Recovery of the corneal transparency and central corneal thickness was delayed in areas of Descemet's membrane removal, but the cell density of the regenerated corneal endothelium and the thickness of the central corneal did not differ between the areas with and without residual Descemet's membrane at 14 days after CEC injection. Here, we demonstrate that removal of a pathological Descemet's membrane by a small descemetorhexis is a feasible procedure for use in combination with cell-based therapy. The current strategy might be beneficial for improving visual quality after CEC injection as a treatment for FECD.

Fuchs' endothelial dystrophy (FED) is characterized by corneal endothelial dysfunction and guttate excrescences on the posterior corneal surface, and is the leading indication for corneal transplantation in developed countries. In severe cases, keratoplasty is considered as the gold standard of treatment. However, there have been significant developments in our understanding of FED over the past decade. Attempts have been made to treat this disease with regenerative therapy techniques such as primary descemetorhexis without an endothelial graft or with a tissue-engineering approach. The discovery of a strong association between the CTG18.1 trinucleotide repeat expansion sequence and FED may pave the way for gene therapy strategies in the future. In this review, we evaluate these novel therapeutic modalities as possible alternatives to keratoplasty as the standard of care for FED.

Purpose: To report the safety and efficacy of descemetorhexis without grafting as a primary intervention in Fuchs dystrophy, and the use of a ROCK inhibitor, ripasudil as a salvage agent in failing cases., Methods: Twelve eyes of 11 patients underwent central descemetorhexis not exceeding 4 mm. All had Fuchs dystrophy-producing visual symptoms, requesting intervention. Exclusion criteria were a peripheral endothelial cell count <1000 and central edema. Corneal clearance and visual parameters were recorded monthly until corneal clearance was observed, then at intervals of 6 months. Cases failing to clear by month 2 were considered for salvage treatment. This consisted of treatment with 1 of 2 formulations of Rho-associated kinase inhibitor eye drops. Endothelial keratoplasty was planned as the final salvage procedure in unsuccessful cases., Results: Nine of 12 eyes cleared spontaneously between 2 and 6 months. One eye failed to clear by month 5 and topical Y-27632 was administered, without success. Endothelial keratoplasty was performed. In 2 eyes, healing stalled at 3 and 2 months. In both cases, topical ripasudil administered 6 times a day for 2 weeks resulted in complete corneal clearance. In cases achieving corneal clearance, best spectacle corrected visual acuity improved from a mean of 0.26 to 0.125 (logMAR) with subjective improvement in quality of vision., Conclusions: In Fuchs dystrophy with visual degradation due to central guttae, descemetorhexis without grafting is a viable procedure for visual rehabilitation. Careful patient selection is required, but the advent of topical ripasudil as a salvage agent suggests that a broader application of the surgery may be possible. Further study into the use of this agent is now needed.

Fuchs endothelial corneal dystrophy is the most common genetically determined degenerative disease of the cornea. In Polish patients the dystrophy is a leading indication for lamellar posterior keratoplasty. The genetic background of Fuchs endothelial corneal dystrophy is complex and heterogeneous. A number of TCF4 gene variants have been strongly associated with the development of this disorder with the most important of them being the trinucleotide repeat expansion CTG18.1. The aim of the study is to present this novel and extraordinarily strong genetic association with Fuchs endothelial corneal dystrophy. Studies on the impact of CTG18.1 on corneal endothelial cells may help to explain the molecular mechanism involved in the pathogenesis of the corneal dystrophy. This could significantly improve diagnostics and therapy of Fuchs endothelial corneal dystrophy patients.

Decompensation of the corneal endothelium causes severe visual impairments that lead to blindness. Although corneal transplantation is a well-known effective therapy for corneal endothelial dysfunction, many patients are not afforded that therapeutic opportunity owing to the worldwide shortage of donor corneas. Thus, a tissue engineering-based therapy for treating corneal endothelial dysfunction is highly anticipated. Obstacles associated with the development of tissue engineering therapy include in vitro culture of corneal endothelial cells (CECs) and the techniques used to transplant those cells. Limited proliferation ability, cellular senescence, and fibroblastic transformation during culture are all problems associated with the cultivation of CECs. In addition, transplantation of cultured CECs is technically difficult because the corneal endothelium is composed of a fragile monolayer sheet of cells located at the posterior cornea. In this review article, we present our recent findings using a novel cell culture protocol and show that modulation of CEC adhesion properties through a Rho-kinase inhibitor enables transplantation of CECs in the form of a cell suspension without the use of a carrier. Finally, we provide an update on the clinical application status of a cell-based therapy for treating corneal endothelial dysfunction.

Purpose: Fuchs endothelial corneal dystrophy (FECD) is an oxidative stress disorder that leads to age-related and gradual loss of corneal endothelial cells resulting in corneal edema and loss of vision. To date, other than surgical intervention, there are no treatment options for patients with FECD. We have shown that in FECD, there is a deficiency in nuclear factor erythroid 2-related factor 2 (Nrf2)-regulated antioxidant defense due to decreased Nrf2 nuclear translocation and activation of antioxidant response element (ARE). In this study, we used sulforaphane (SFN) and D3T to investigate a strategy of targeting Nrf2-ARE in FECD., Methods: FECD and normal ex vivo corneas and human corneal endothelial cell lines were pretreated with SFN or D3T and exposed to oxidative stress with tert-Butyl hydroperoxide (tBHP). Apoptosis was detected with TUNEL. Cellular localization of Nrf2 and p53 was assessed by immunohistochemistry. Effect of SFN was determined by using DCFDA assay, Western blot and real-time PCR., Results: After pretreatment with SFN, oxidative stress was induced with tBHP. In ex vivo FECD specimens, SFN decreased CEC apoptosis by 55% in unstressed group and by 43% in tBHP-treated specimens. SFN enhanced nuclear translocation of Nrf2 in FECD specimens and decreased p53 staining under oxidative stress. Pretreatment with SFN enhanced cell viability by decreasing intracellular reactive oxygen species production. Upregulation of Nrf2 levels led to increased synthesis of DJ-1, heme oxygenase 1, and nicotinamide adenine dinucleotide quinone oxidoreductase-1. SFN significantly upregulated major ARE-dependent antioxidants and ameliorated oxidative stress-induced apoptosis in FECD., Conclusions: Our results suggest that targeting Nrf2-ARE pathway may arrest degenerative cell loss seen in FECD.

Fuchs uveitis syndrome (FUS) is typically a unilateral, chronic, low-grade inflammation of the anterior segment which manifests in young adulthood. It is underdiagnosed because of its variable clinical spectrum. Although it can mimic various forms of anterior uveitis, it is important to make the correct diagnosis, based on clinical grounds, because both the management and prognosis differ from those of other uveitides. While its etiology remains unknown, it is possible that the disease has multiple causes that lead through different pathogenic mechanisms to the same clinical entity. Although many patients do not require treatment, it is not a benign condition, as often perceived. The high incidence of glaucoma makes it mandatory that all patients with FUS should be screened at regular intervals, even if they are not being actively treated and are relatively asymptomatic.

Fuchs' endothelial dystrophy is a common disease that has been widely studied since its initial report in 1910 by Ernst Fuchs. Although its clinical course and pathologic characteristics are well described, the etiology and inheritance pattern are still ambiguous. Ongoing work is evaluating the role of mitochondrial DNA in the pathogenesis of FED. Significant advances in the surgical treatment of FED, in part utilizing some of the techniques of refractive surgery, are promising thus far. Larger case series are needed to fully assess the safety, efficacy and indications of these techniques. Indeed, the time is right to take "a fresh look at an aging disease" [9].

The increasing number or corneal and intraocular surgeries performed together with longer life expectancy, elevates the risk for developing symptomatic Fuchs' endothelial dystrophy (FED). This article reviews the current understanding of FED, and, in addition, a case of early FED is presented clinically and histopathologically. Two FED corneas from one patient were examined histopathologically using an established histological protocol for light and electron microscopy. FED is an inherited autosomal dominant corneal endothelial disorder with incomplete penetrance that is up to 3 times less likely to develop in men. Treatment options are primarily palliative while surgical intervention routinely involves a penetrating keratoplasty. In this disease process the endothelium produces excessive amounts of basement membrane material of an abnormal composition resulting in the formation of a posterior collagenous layer. Extreme accumulations of this material created mushroom-like formations, guttae, projecting into the anterior chamber. The endothelial cells were extremely thinned over the guttae, to the point where the cells may provide little more than barrier function. Despite a presumably compromised endothelial pump the corneas appeared relatively free of edema clinically and histopathologically. However, some edematous pockets deep in the basal epithelial layer were present suggesting that epithelial involvement occurs at an early stage in the disease. An early diagnosis of FED will help patients and surgeons to better elect optimal surgical timing and procedures. The current trend is to intervene surgically before the patient reaches the painful end-stage. Interestingly, in the case examined, the endothelium presumably provided only a barrier function over large areas with an apparently reduced contribution from the endothelial fluid pump and yet the corneas remained relatively clear. Future research may confirm that decompensation occurs only when complete endothelial coverage is lost. If the endothelial barrier function is more important to corneal transparency than the endothelial pump function in FED, then the relative combination of these two functions in the normal cornea should also be reassessed.

Fuchs' endothelial dystrophy of the cornea is a significant cause of corneal blindness in the United States. The disease is characterized by a slow, continuous loss of morphologically and physiologically altered endothelial cells, eventually leading to corneal edema. The endothelial cells synthesize a thickened Descemet's membrane with focal excrescences of altered basement membrane material (guttae). This review details the epidemiological, clinical, and laboratory data that have accumulated on Fuchs' dystrophy. Several hypotheses regarding the pathogenesis of Fuchs' dystrophy are discussed, including the possible influences of aberrant embryogenesis, hormones, and injury on the development of the disease. The current state of medical and surgical management is summarized, along with the future prospects for treatment.

Corneal dystrophies are inherited (usually autosomal dominant) disorders involving virtually every layer of the cornea. They result in opacities of various sizes and shapes that primarily affect the central cornea relatively early in life. Diagnosis is most often based on clinical appearance and careful biomicroscopic examination to assess the corneal layer(s) that are affected. Because most dystrophies are slowly progressive, visual acuity is often minimally affected for much of an individual's lifetime. Dystrophies are not associated with any prior corneal inflammations or systemic disease. This paper is a discussion of the most commonly encountered dystrophies affecting the epithelium, Bowman's membrane, stroma, and endothelium. The optometric management of many of these dystrophies may, at times, present a challenge to the clinician. Treatment may range anywhere from a simple therapeutic contact lens to referral for penetrating keratoplasty.

Fuchs's endothelial dystrophy interferes with removal of fluid from the cornea by the endothelium. It progresses through stages of corneal guttata, corneal edema, bullous keratopathy, vascularization, and scarring, and complications such as glaucoma or infection. The optometrist can detect this disorder and manage its early stages as well as provide counseling and proper referral. This paper includes a case study and a discussion of the course and treatment of this disease.

Fuchs' dystrophy is an inherited disorder of unknown etiology in which the corneal endothelial cells develop morphologic and functional abnormalities. Clinically, the disease progresses slowly over a period of 20 or more years from asymptomatic cornea guttata to corneal edema with decreased vision and pain. Pathologic studies suggest abnormalities in endothelial function occurring early in life, although symptoms usually do not appear until middle age. The definitive treatment for Fuchs' dystrophy is penetrating keratoplasty. Recent findings regarding the pathophysiology of the disease have increased our understanding of it and have suggested areas for future research.