Poly (glycerol sebacate)-poly (ε-caprolactone) blend nanofibrous scaffold as intrinsic bio- and immunocompatible system for corneal repair

A major challenge in corneal tissue engineering and lamellar corneal transplantation is to develop synthetic scaffolds able to simulate the optical and mechanical properties of the native cornea. As a carrier, the graft scaffolds should provide the basis for anchorage, repair and regeneration. Although quite a number of scaffolds have been engineered to date, they have not been able to simultaneously recapitulate chemical, mechanical, and structural properties of the corneal extracellular matrix (ECM). Here, we examined different compositions of elastomeric biodegradable poly (glycerol sebacate) (PGS)-poly (ε-caprolactone) (PCL) nanofibrous scaffolds with respect to their cyto- and immunocompatibility. These scaffolds were semi-transparent with well-defined mechanical properties and direct positive effects on viability of human corneal endothelial cells (HCEC) and human conjunctival epithelial cells (HCjEC). Moreover, within 3days HCEC established monolayers with the hexagonal morphology typical for this cell type. All PGS-PCL mixtures analyzed did not trigger effects in granulocytes, naïve and activated peripheral blood mononuclear cells (PBMCs). However, scaffolds with a higher content of PGS-PCL ratio showed the best cell organization, cyto- and immunocompatibility. Subsequently, this PGS-PCL composition could be used for further development of clinical constructs to support corneal tissue repair.

STATEMENT OF SIGNIFICANCE

In corneal tissue engineering a major challenge is the development of synthetic scaffolds with similar properties to native cornea. In our recent works, we introduced the biodegradable, polymeric nanofibrous scaffolds with similar optical and mechanical properties for corneal regeneration and here we examined the cyto- and immunocompatibility of biodegradable nanofibrous scaffolds in contact to white blood cells. Directing the alignment of human corneal cells by nanofibrous scaffolds and high viability of cells was detected by forming of endothelium monolayer with hexagonal morphology on the nanofibrous scaffold. In addition, our results for the first time show that these nanofibrous scaffolds did not trigger effects in white blood cells. These results highlight the considerable translational potential of the nanofibrous scaffolds to clinical applications.

Anti-apoptotic gene therapy prolongs survival of corneal endothelial cells during storage

Corneal transplantation is the most common form of grafting performed worldwide. Corneal endothelial cells (EC) form a monolayer in the posterior portion of the cornea and are essential for corneal transparency. EC loss during storage before transplantation is a principal reason for rendering donor tissue unsuitable for transplantation, and apoptosis has been shown to be the major contributor to EC loss during storage and after transplantation. Therefore, the potential use of anti-apoptotic gene therapy to promote both graft storage and graft survival is of major interest. The goal of this study was to transduce human donor corneas in vitro to enhance EC survival during storage conditions used in eye banking. We utilized a lentiviral vector to perform gene transfer of baculoviral p35 or mammalian Bcl-xL to corneal endothelium in different storage conditions utilizing a lentiviral vector. Our results show significantly enhanced survival and prolonged retention of physiological EC morphology in cells expressing either p35 or Bcl-xL. The clinical application of this technology could lead to a higher availability of donor tissue for transplantation, extend storage periods and reduce graft failure after transplantation.

Corneal endothelial cells are protected from apoptosis by gene therapy

Corneal grafting is the most prevalent form of transplantation. Corneal endothelial cells (ECs), which form a monolayer of the cornea with minimal proliferative potential, are pivotal for maintenance of corneal clarity. Loss of EC viability and apoptosis leads to graft failure posttransplantation and reduces the quality of donor corneas in storage, such that up to 30% do not meet selection criteria and must be discarded. The current study investigates antiapoptotic effects of transduced mammalian Bcl-x(L) and baculoviral p35 on human ECs. Multiple apoptotic cell features are observed while inducing apoptosis either via the extrinsic (death receptor) or intrinsic (mitochondrial) apoptotic pathway. Human ECs were studied under three experimental conditions: (1) as an immortalized cell line, (2) as primary cells, and (3) in an intact cornea. Interestingly, in primary EC suspensions, Bcl-x(L) was protective against apoptosis mediated via both pathways. However, p35 was significantly more protective against apoptosis mediated via the intrinsic pathway compared with Bcl-x(L). Our results provide critical insight into the role of apoptotic pathways in the maintenance of EC viability and the efficacy with which these protective proteins exert their effect. These observations could form the basis for future applications of antiapoptotic gene therapy to corneal preservation aiming to reduce both graft failure after transplantation as well as donor corneal damage during storage.

The influence of donor factors on corneal organ culture contamination

PURPOSE

To evaluate the contamination rate and the corresponding spectrum of microbes and to identify donor risk factors for corneal organ culture contaminations.

METHODS

A total of 3306 organ-cultured donor corneas were included in the study. We performed a retrospective database analysis to evaluate donor factors such as gender, age, death-to-explantation interval (DEI), procurement site and cause of death and to determine their influence on donor cornea contaminations. Odds ratios (ORs) were calculated for each factor.

RESULTS

The overall contamination rate was 7.8% (n = 259). Younger donor age (OR: 2.2, p = 0.003, chi-squared test), a DEI of more than 24 hr (OR: 1.6, p < 0.001), hospitalization prior to death (OR: 2.2, p < 0.001) and death caused by sepsis (OR: 2.7, p < 0.001) were associated with an increased risk of contamination, whereas donor gender did not have an effect on donor cornea contaminations. The most frequently isolated microbes were Enterococci (19%), Staphylococci (10.8%) and Candida (37.4%).

CONCLUSION

This study helps to estimate the contamination risk of a cultured cornea based on specific donor factors. However, donors with risk factors should not be generally excluded from cornea donation. Further studies including antibiograms might clarify whether a change in the antibiotic composition of the culture medium would be useful to deal with the increasing number of multi-resistant microbes.

Efficient and safe gene delivery to human corneal endothelium using magnetic nanoparticles

Aim: To develop a safe and efficient method for targeted, anti-apoptotic gene therapy of corneal endothelial cells (CECs). Materials & methods: Magnetofection (MF), a combination of lipofection with magnetic nanoparticles (MNPs; PEI-Mag2, SO-Mag5, PalD1-Mag1), was tested in human CECs and in explanted human corneas. Effects on cell viability and function were investigated. Immunocompatibility was assessed in human peripheral blood mononuclear cells. Results: Silica iron-oxide MNPs (SO-Mag5) combined with X-tremeGENE-HP achieved high transfection efficiency in human CECs and explanted human corneas, without altering cell viability or function. Magnetofection caused no immunomodulatory effects in human peripheral blood mononuclear cells. Magnetofection with anti-apoptotic P35 gene effectively blocked apoptosis in CECs. Conclusion: Magnetofection is a promising tool for gene therapy of corneal endothelial cells with potential for targeted on-site delivery.

Argon Cold Plasma-A Novel Tool to Treat Therapy-resistant Corneal Infections

PURPOSE

To test whether therapy-resistant corneal infections can be successfully treated with argon cold plasma to reduce or eliminate pathogen microorganisms without affecting corneal cell viability.

DESIGN

First-in-human case series and experimental study.

METHODS

Cold plasma effects on viability of primary human corneal limbal epithelial cells were studied using exposure times from 0.5 to 10 minutes (metabolic activity, oxidative stress, apoptosis). Disinfective potential of cold plasma was tested against common pathogens (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans) on culture medium and evaluated by counting colony-forming units and optical density measurements, as well as against S aureus in a human cornea infection model. Additionally, in a first-in-human trial 4 patients with therapy-resistant corneal ulcers were treated to evaluate the clinical potential of cold plasma.

RESULTS

Cells treated for 0.5-5 minutes completely recovered within 24 hours without changes in morphology; only 10-minute treatment impaired the cells permanently. No evident oxidative stress, apoptosis, or damage to the corneal structure could be found. All pathogens were susceptible to cold plasma treatments, with different levels of sensitivity. The condition of all 4 patients significantly improved after cold plasma treatment combined with antibiotic therapy.

CONCLUSIONS

Our results indicate that argon cold plasma treatment reduces or eliminates common pathogens without impairing corneal epithelial cells in vitro, ex vivo, and in direct application on patients' eyes. We conclude that argon cold plasma therapy offers a potential supplement or alternative therapy for therapy-resistant corneal infections. A larger, comparative study is necessary to further confirm these findings.

Adjuvante topische Interferon-α-2b-Therapie bei epithelialen Tumoren der Augenoberfläche

PURPOSE

The aim of this study was to evaluate the role of topical interferon-alpha-2b in the adjuvant treatment of corneal and conjunctival tumors.

METHOD

In this noncomparative, prospective, interventional case series, five patients with histologically proven conjunctival intraepithelial neoplasia (CIN) after primary excision and amniotic membrane transplantation were treated with interferon (IFN)-alpha-2b eye drops five times daily over a period of 6 weeks (1 million IU/ml Intron A, Schering). An in situ hybridization technique was used to detect human papillomavirus (HPV) in all specimens. Frequent follow-up was undertaken clinically and photographically for evidence of tumor recurrence.

RESULTS

In the follow-up period (13.2+/-4,97 months) no clinical evidence of recurrence with only limited treatment side effects such as mild conjunctival hyperemia were recorded after 6 weeks of interferon. In one CIN specimen HPV 16/18 could be detected.

CONCLUSIONS

The combination of excisional biopsy and topical interferon-alpha-2b application seems to be an effective and safe treatment for conjunctival intraepithelial neoplasias. Therefore, we prefer this combined treatment to topical interferon-alpha-2b treatment alone, more destructive approaches such as radiation and cryotherapy, or treatment with antimetabolites such as 5-fluorouracil or mitomycin C.

Biomechanical assessment of healthy and keratoconic corneas (with/without crosslinking) using dynamic ultrahigh-speed Scheimpflug technology and the relevance of the parameter (A1L-A2L)

AIMS

To examine corneal biomechanics in healthy and keratoconic eyes, with or without crosslinking obtained by ultrahigh-speed Scheimpflug measurements (Corvis ST).

METHODS

One hundred and seventeen eyes were studied in three groups: group 1 (n=39) contained keratoconic eyes without crosslinking. Group 2 (CXL; n=28) comprised keratoconic eyes after crosslinking. These were compared with a control group (n=50 matched healthy eyes). In addition, 10 keratoconus patients, before and after CXL treatment, respectively, were examined.

RESULTS

The novel parameter A1L-A2L demonstrated highly significant differences between crosslinked corneas and untreated keratoconic or healthy corneas. Velocity during second applanation (A2V) and deformation amplitude (DA) were significantly increased in crosslinked keratoconic eyes both compared with untreated keratoconic eyes and with healthy controls. Radius at highest curvature also was significant among all groups. Inward applanation length (A1L) was significantly increased in controls, whereas outward applanation length (A2L) was significantly reduced in crosslinked keratoconic eyes compared with both other groups. The follow-up analysis revealed statistically significant changes in pachymetry and intraocular pressure and showed tendencies towards significance in applanation times 1 and 2 and in DA.

CONCLUSIONS

Both A2V and A2L are viable parameters to discriminate healthy from keratoconic but also crosslinked from non-crosslinked keratoconic corneas. The difference of A1L-A2L could reliably discriminate crosslinked from non-crosslinked and healthy corneas. Follow-up examination in a small cohort allows distinction between crosslinked and untreated keratoconus in follow-up examinations. The difference of A1L-A2L could reliably discriminate crosslinked from non-crosslinked and healthy corneas. Measurements of corneal deformation using dynamic ultrahigh-speed Scheimpflug technology are reproducible and provide useful information about keratoconus assessment and biomechanics. Therefore, the Corvis ST seems to provide useful technology to monitor therapeutic success of crosslinking treatment.

A novel suture retention test for scaffold strength characterization in ophthalmology

Sutures are a common way to attach scaffolds in patients. For tubular cardiac scaffolds, the 'suture retention strength' is commonly used to evaluate the resistance of a scaffold against the pull-out of a suture. In order to make this quantity accessible for ophthalmological scaffolds the test procedure has been modified in a novel way. Polycaprolactone (PCL) films of different thicknesses and an amniotic membrane (AM) were used for the experiments. Circular samples with a radius of 7mm were taken and a suture was passed through each sample and tied to a loop. The sample was clamped in a tensile tester and a bolt was passed through the loop. The suture was then pulled with a constant deformation rate until pull-out occurred. The suture retention strength, the deformation at the suture retention strength, and the deformation at rupture were determined for each sample. The presented modified suture retention test allows to measure the relevant parameters of samples on the scale of ophthalmological scaffolds in a reproducible way. A comparison between the first data on PCL and AM has been made.

[Neurotrophic keratopathy--a post-LASIK case report]

BACKGROUND

Neurotrophic keratopathy is a degenerative affection of the cornea caused by impairment of corneal sensitivity and represents a therapeutic challenge for ophthalmologists. The present article concentrates on the etiology, pathogenesis, diagnosis, therapeutic aspects and future therapeutic models for treating neurotrophic keratopathy and will present a case report: Also we evaluate the effects of autologous serum eye drops in bilateral LASIK-induced neurotrophic keratopathy with epithelial breakdown revealed by positive fluorescence and rose bengal staining and reduced tear film break-up time.

METHODS

We treated a 42-year-old patient with post-LASIK neurotrophic keratopathy and tear film instability with autologous serum eye drops (5 x daily) and emulsion eye drops (Refresh Endura, Allergan, Irvine, CA, USA) after insertion of punctal plugs.

RESULTS

Stabilization of vision, healing of the epithelium and reduction of the previously experienced symptoms like redness, itching and burning were achieved within 6 weeks. 10 months after changing therapy, the patient only complained about slight pain during lid movement.

CONCLUSIONS

Severe denervation after bilateral LASIK disrupts ocular tear film dynamics and causes irritation symptoms of the ocular surface. Autologous serum eye drops may be an effective treatment of severe epithelial breakdown and be helpful to reestablish the disturbed ocular surface integrity, as shown by negative vital staining. Therefore, autologous serum eye drops represent a significant approach in the therapy of LASIK-induced severe dry eye and associated pain.

Electrospun PCL Scaffolds as Drug Carrier for Corneal Wound Dressing Using Layer-by-Layer Coating of Hyaluronic Acid and Heparin

Due to its ability to reduce scarring and inflammation, human amniotic membrane is a widely used graft for wound dressings after corneal surgery. To overcome donor dependency and biological variances in the donor tissue, artificial nanofibrous grafts acting as drug carrier systems are promising substitutes. Electrospun nanofibrous scaffolds seem to be an appropriate approach as they offer the properties of permeable scaffolds with a high specific surface, the latter one depending on the fiber diameter. Electrospun scaffolds with fiber diameter of 35 nm, 113 nm, 167 nm and 549 nm were manufactured and coated by the layer-by-layer (LbL) technology with either hyaluronic acid or heparin for enhanced regeneration of corneal tissue after surgery. Studies on drug loading capacity and release kinetics defined a lower limit for nanofibrous scaffolds for effective drug loading. Additionally, scaffold characteristics and resulting mechanical properties from the application-oriented characterization of suture pullout from suture retention tests were examined. Finally, scaffolds consisting of nanofibers with a mean fiber diameter of 113 nm were identified as the best-performing scaffolds, concerning drug loading efficiency and resistance against suture pullout.

Examining the Transmission of Visible Light through Electrospun Nanofibrous PCL Scaffolds for Corneal Tissue Engineering

The transparency of nanofibrous scaffolds is of highest interest for potential applications like corneal wound dressings in corneal tissue engineering. In this study, we provide a detailed analysis of light transmission through electrospun polycaprolactone (PCL) scaffolds. PCL scaffolds were produced via electrospinning, with fiber diameters in the range from (35 ± 13) nm to (167 ± 35) nm. Light transmission measurements were conducted using UV-vis spectroscopy in the range of visible light and analyzed with respect to the influence of scaffold thickness, fiber diameter, and surrounding medium. Contour plots were compiled for a straightforward access to light transmission values for arbitrary scaffold thicknesses. Depending on the fiber diameter, transmission values between 15% and 75% were observed for scaffold thicknesses of 10 µm. With a decreasing fiber diameter, light transmission could be improved, as well as with matching refractive indices of fiber material and medium. For corneal tissue engineering, scaffolds should be designed as thin as possible and fabricated from polymers with a matching refractive index to that of the human cornea. Concerning fiber diameter, smaller fiber diameters should be favored for maximizing graft transparency. Finally, a novel, semi-empirical formulation of light transmission through nanofibrous scaffolds is presented.

Gene Therapy for Modulation of T-Cell-Mediated Immune Response Provoked by Corneal Transplantation

Corneal transplantation (keratoplasty) is the most common type of tissue replacement in the world. The increased rate of graft rejection after keratoplasty is a central problem for repeated transplantations and in inflamed host corneas. It has been shown that apoptosis of grafted epithelium has a role in corneal allograft rejection. This study focused on the T-cell response triggered in BALB/c mice after allogeneic corneal transplantation with and without anti-apoptotic p35-transduced epithelium. To restrict p35 expression to the epithelial cells, modified allogeneic composite grafts were created. As a result, it was found that the proportion of alloreactive CD4⁺ T cells in postoperatively removed cervical lymph nodes was reduced in the p35-transduced group compared to the allogeneic control group. Diminished priming of the CD4⁺ T cells was supported by significantly decreased proliferation and lower interferon gamma secretion when compared to allogeneic engraftments. The reduced priming of CD4⁺ lymphocytes is the first confirmation of the functionality of p35 in the epithelium of corneal grafts to alter the development of the recipient's immune response. Thus, modification of allosensibilization seems to be a promising tool for reducing graft-mediated immune response following corneal transplantation.

Lamin Cleavage: A Reliable Marker for Studying Staurosporine-Induced Apoptosis in Corneal Tissue

Purpose

The aims of this study were to identify a robust apoptosis marker suitable for both quantification and back-to-back analyses of programmed cell death and to define specific upstream targets for apoptosis in corneal cells.

Methods

Apoptotic cleavage of initiator caspases and their downstream targets such as lamins and poly-ADP ribose polymerase was investigated in human corneal endothelial cells (HCEC-12), keratocytes (HCK), epithelial cells (HCEp), and full-thickness corneas using Western blotting and confocal microscopy following apoptosis induction with staurosporine. We specifically focused on nuclear lamins, which have important structural and regulatory functions in the cell nucleus.

Results

The cleavage of lamin A in HCEC-12 was significantly increased following apoptotic induction compared with HCK. More importantly, lamin A cleavage was detected in a dose-dependent manner in full-thickness corneal tissue by both Western blot analysis and fluorescence microscopy. Our study also demonstrates that HCEp show approximately three-fold increase in caspase 6 cleavage compared with endothelial cells or keratocytes. The presence of cleaved caspase 9 was lower in endothelial cells compared with epithelial cells and keratocytes.

Conclusions

We successfully established lamin A cleavage as a quantifiable marker of apoptosis in both corneal cells and tissue. Quantification of lamin A cleavage by Western blotting followed by a back-to-back analysis with fluorescence microscopy was studied for the first time in the experimental (donor) corneal tissue. Screening of downstream apoptosis proteins and establishing cell type-specific protocols allowed us to identify possible targets (caspases, Apaf-1, etc.) for protective therapeutic approaches.

[Protection of corneal endothelium from apoptosis by gene and cell therapy]

Protection of corneal endothelium from apoptosis using gene and cell therapy is in a translational phase. This approach offers advantages for eye banking and after transplantation. Safe vehicles for gene or cell therapeutic transduction of corneal endothelium with nucleic acids are available. This strategy will be further developed in consultation with the Paul Ehrlich Institute and European regulatory authorities.

Anatomical and functional results after vitrectomy with conventional ILM peeling versus inverted ILM flap technique in large full-thickness macular holes

BACKGROUND

Aim of the study was to compare success rate and functional outcome following pars plana vitrectomy (PPV) with conventional internal limiting membrane (ILM) peeling versus ILM flap technique for full-thickness idiopathic macular holes (FTMH).

METHODS

Retrospective analysis of consecutive eyes with FTMH having undergone vitrectomy with sulfur hexafluoride (SF6) endotamponade 25% at the University Medical Center Rostock, Germany (2009-2020). Eyes were divided according to applied surgical technique (ILM peeling [group P] versus ILM flap [group F]). Inclusion criteria were macular hole base diameters (MH-BD) ≥ 400 μm plus axial length ≤ 26.0 mm. Each group was divided into two subgroups based on macular hole minimum linear diameter (MH-MLD): ≤ 400 μm and > 400 μm. Exclusion criteria were FTMH with MH-BD < 400 μm, trauma, myopia with axial length > 26.0 mm or macular schisis. Demographic, functional, and anatomical data were obtained pre- and postoperatively. Preoperative MH-BD and MH-MLD were measured using optical coherence tomography (OCT; Spectralis®, Heidelberg Engineering GmbH, Heidelberg, Germany). Main outcome parameter were: primary closure rate, best-corrected visual acuity (BCVA), and re-surgery rate.

RESULTS

Overall 117 eyes of 117 patients with FTMH could be included, thereof 52 eyes underwent conventional ILM peeling (group P) and 65 additional ILM flap (group F) technique. Macular hole closure was achieved in 31 eyes (59.6%) in group P and in 59 eyes (90.8%) in group F (p < 0.001). Secondary PPV was required in 21 eyes (40.4%) in group P and in 6 eyes (9.2%) in group F. Postoperative BCVA at first follow-up in eyes with surgical closure showed no significant difference for both groups (MH-MLD ≤ 400 μm: p = 0.740); MH-MLD > 400 μm: p = 0.241).

CONCLUSION

Anatomical results and surgical closure rate following ILM flap technique seems to be superior to conventional ILM peeling for treatment of FTMH.

PREVALENCE OF SARS-CoV-2 RNA AND ANTIBODY DETECTION, AND VACCINATION STATUS IN PATIENTS WITH OCULAR VASCULAR OCCLUSION

PURPOSE

To analyze the annual prevalence of ocular vascular occlusion in relation to COVID-19 infection and vaccination status in a prospective study.

METHODS

All patients were examined for an active severe acute respiratory syndrome coronavirus 2 infection by RNA detection and for a previous infection by virus-specific antibody detection, and their vaccination status was documented. Data from pandemic year 2020 and previous years, before COVID-19 (2019, 2018, 2017), were retrospectively analyzed.

RESULTS

In 2021, a total of 103 patients with the first diagnosis of ocular vascular occlusion were treated. Most frequent subdiagnoses were central retinal vein occlusion (20.4%), nonarteritic anterior ischemic optic neuropathy (18.4%), central retinal artery occlusion (13.6%), and branch retinal artery occlusion (12.6%). Thereof, only three patients (2.9%) presented with virus-specific severe acute respiratory syndrome coronavirus 2 antibodies, and none was PCR positive. Patients with preceded severe acute respiratory syndrome coronavirus 2 vaccination (59.2%) presented with comparable characteristics as unvaccinated patients with vascular occlusion regarding age, gender distribution, systemic risk factors, duration of symptoms, visual acuity, and the present subdiagnoses ( P > 0.05). The total number of cases in 2021 (103 cases) was comparable with the pandemic year 2020, at which no vaccination was available (114 cases), and to earlier years 2017, 2018, and 2019 without COVID-19 pandemic (100, 120, and 119 cases). Furthermore, we did not reveal any differences between pandemic and reference years regarding patients' characteristics ( P > 0.05).

CONCLUSION

Our study did not reveal an increased annual prevalence of ocular vascular occlusions during COVID-19 pandemic years 2020 and 2021. Patients with previous COVID-19 vaccination did not present differences regarding the risk profile nor symptoms, compared with unvaccinated individuals.

Suppressing Pro-Apoptotic Proteins by siRNA in Corneal Endothelial Cells Protects against Cell Death

Corneal endothelial cells (CE) are critical for the cornea's transparency. For severe corneal damage, corneal tissue transplantation is the most promising option for restoring vision. However, CE apoptotic cell death occurs during the storage of donor corneas for transplantation. This study used small interfering (si)RNA-mediated silencing of pro-apoptotic proteins as a novel strategy to protect CE against apoptosis. Therefore, the pro-apoptotic proteins Bax and Bak were silenced in the human corneal endothelial cell line (HCEC-12) by transfection with Accell™siRNA without any adverse effects on cell viability. When apoptosis was induced, e.g., etoposide, the caspase-3 activity and Annexin V-FITC/PI assay indicated a significantly reduced apoptosis rate in Bax+Bak-siRNA transfected HCECs compared to control (w/o siRNA). TUNEL assay in HCECs exposed also significantly lower cell death in Bax+Bak-siRNA (7.5%) compared to control (w/o siRNA: 32.8%). In ex vivo donor corneas, a significant reduction of TUNEL-positive CEs in Bax+Bak-siRNA corneas (8.1%) was detectable compared to control-treated corneas (w/o siRNA: 27.9%). In this study, we demonstrated that suppressing pro-apoptotic siRNA leads to inhibiting CE apoptosis. Gene therapy with siRNA may open a new translational approach for corneal tissue treatment in the eye bank before transplantation, leading to graft protection and prolonged graft survival.