Epithelial Debridement Research Articles

Alcohol-assisted epithelial debridement for treatment of recurrent corneal erosion: a case series

Purpose: Recurrent corneal erosion is characterized by recurrent episodes of spontaneous breakdown of the corneal epithelium. Alcohol delamination of the corneal epithelium has a high success rate, but the procedure requires the use of an operating microscope in an operating theater. We present a case series of alcohol assisted epithelial debridement in the clinic setting. Methods: Records of eight consecutive patients aged >18 years who presented to a private ophthalmology practice clinic in Hong Kong between October 2012 and March 2018 with recurrent corneal erosion that did not respond well to conservative or surgical management with persistent symptoms of >3 months were retrospectively reviewed. 75% alcohol was applied directly to the site of abnormal epithelium under slit lamp, followed by debridement of the epithelium using a surgical sponge. A bandage contact lens was then inserted. Patients were followed up until complete healing of the epithelial defect. Results: All eight patients achieved complete healing of the epithelial defect within 2 weeks with no major complication or recurrence. Conclusion: Alcohol-assisted epithelial debridement is simple, safe, and effective for the treatment of recurrent corneal erosion. It can be performed in a clinic setting under slit lamp.

A CARE-compliant article: optical coherence tomography for epithelial basement membrane dystrophy

Rationale:The etiology of anterior corneal opacities and the effect of debridement cannot be determined by biomicroscopy. Optical coherence tomography (OCT) helps identify the character and depth of these lesions.Patient concerns:A 45-year-old female complained of progressive blurred vision for a long time. Slit lamp biomicroscopy showed irregular, faint scar-like opacity of anterior cornea in her both eyes. Pentacam Scheimpflug camera tomography showed irregular astigmatism of anterior corneal surface. Anterior segment spectral-domain OCT revealed thickened, hyper-reflective linings, and scattered lesions, mainly in the epithelial layer.Diagnoses:Epithelial basement membrane dystrophy (EBMD).Intervention:Epithelial debridement and bandage lenses.Outcomes:The cornea became clear and the vision improved soon after debridement. The pathology showed thickened aberrant basement membrane extending into mid-epithelial layer, with microcyst-like lesions also noted.Lessons:OCT defines the depth of lesions and helps diagnosis and management of EBMD.

Staphylococcus aureus alpha-hemolysin impairs corneal epithelial wound healing and promotes intracellular bacterial invasion

Colonization by Staphylococcus aureus (S. aureus) has been implicated in many infectious and wound healing disorders. This study was performed to characterize the pathogenic role of S. aureus alpha-hemolysin (alpha-toxin) in corneal epithelial wound healing and infectious keratitis in the setting of a corneal wound. The effect of wild-type and isogenic Hla mutant (α-hemolysin gene deleted) S. aureus bacteria and conditioned media on corneal epithelial wound healing was tested in vitro using a scratch assay and in vivo using a murine epithelial debridement model. The invasiveness of wild-type and Hla mutant S. aureus was evaluated in vitro in human corneal epithelial cells and in vivo in a murine model of infectious keratitis following total epithelial debridement. S. aureus and its conditioned media significantly delayed epithelial wound closure both in vitro (P < 0.05) and in vivo (P < 0.05). The effect of S. aureus on wound healing was significantly diminished with the Hla mutant strain (P < 0.05). Likewise, compared to the wild-type strain, the Hla mutant strain demonstrated significantly reduced ability to invade corneal epithelial cells in vitro (P < 0.05) and infect murine corneas following total epithelial debridement in vivo (P < 0.05). In conclusion, S. aureus alpha-hemolysin plays a major role in the pathologic modulation of corneal epithelial wound healing and the intracellular invasion of the bacteria. Limiting colonization by S. aureus and/or blocking alpha-hemolysin may provide a therapeutic approach for corneal wound healing and infectious disorders.

DNA Methylation Regulates Corneal Epithelial Wound Healing by Targeting miR-200a and CDKN2B

DNA methylation is a key epigenetic modification involved in various biological processes and diseases. Corneal epithelial wound healing (CEWH) is essential for restoring corneal integrity and transparency after injury. However, the role of DNA methylation in CEWH remains elusive. Here, we investigate the function and underlying mechanism of DNA methylation in regulating CEWH. Dot blots and global methylation assays determined DNA methylation levels during CEWH. Quantitative RT-PCR and Western blot analysis examined the expression of DNA methyltransferases (DNMTs), cyclin-dependent kinase inhibitor 2B (CDKN2B), and miR-200a during CEWH, respectively. MTS assays and flow cytometry were used to analyze human corneal epithelial cell (HCEC) proliferation and cell cycle, respectively. The in vitro scratch wound assay assessed HCEC migration and an in vivo murine corneal epithelial debridement model evaluated wound healing. Using bisulfite sequencing PCR, we determined the DNA methylation status of the candidate genes. Transfection of miR-200a mimic or inhibitor assessed the function of miR-200a in HCECs. Rescue experiments were performed to clarify the correlation between DNMT1 and miR-200a/CDKN2B during CEWH. DNMT1 and DNMT3B expression was significantly upregulated during CEWH, resulting in a significant global DNA hypermethylation. DNMT1 downregulation dramatically delayed CEWH in vivo, and suppressed HCEC proliferation and migration. MiR-200a inhibited HCEC migration. Furthermore, miR-200a and CDKN2B were identified as molecular targets of DNA methylation and as having a causal connection with DNMT1. DNMT1-mediated DNA hypermethylation can enhance the process of CEWH by directly targeting miR-200a and CDKN2B. This insight pinpoints novel potential drug targets for promoting CEWH.

Recurrent corneal erosion: a comprehensive review.

PurposeTo comprehensively review the literature regarding recurrent corneal erosion (RCE) and to present treatment options and recommendations for management.OverviewRCE usually presents with sharp, unilateral pain upon awakening, in an eye with an underlying basement membrane dystrophy, prior ocular trauma, stromal dystrophy or degeneration, or prior surgery for refractive errors, cataracts, or corneal transplantation. Making the correct diagnosis requires a careful slit-lamp examination of both eyes coupled with a high degree of suspicion. Several treatments are commonly used for RCE but new therapies have been introduced recently. Conservative treatment consists of antibiotic and preservative-free lubricating drops, with topical cycloplegics and oral analgesics to control pain. Patients who are unresponsive to these therapies may benefit from therapeutic bandage contact lenses (BCL). Newer therapies include oral matrix metalloproteinase (MMP) inhibitors, blood-derived eye drops, amniotic membrane graft application, and judicious application of topical corticosteroids. Once the epithelium is healed, a course of hypertonic saline solution and/or ointment can be used. Surgical procedures may be performed in patients who fail conservative therapy. Punctal occlusion with plugs increases the tear film volume. Epithelial debridement with diamond burr polishing (DBP), anterior stromal puncture (ASP), or alcohol delamination should be considered in selected patients. DBP can be used for patients with basement membrane dystrophies and is the preferred treatment overall due to a low recurrence rate. ASP can be used for erosions outside the central visual axis. Excimer laser phototherapeutic keratectomy is an attractive option in eyes with central RCE since it precisely removes tissue while preserving corneal transparency. In patients with RCE who are also candidates for refractive surgery, photorefractive keratectomy can be considered.SummaryNewly introduced therapies for RCE enable therapy to be individualized and lower the recurrence rate.

Induction of Fibroblast Senescence During Mouse Corneal Wound Healing.

To investigate the presence and role of fibroblast senescence in the dynamic process of corneal wound healing involving stromal cell apoptosis, proliferation, and differentiation. An in vivo corneal wound healing model was performed using epithelial debridement in C57BL/6 mice. The corneas were stained using TUNEL, Ki67, and α-smooth muscle actin (α-SMA) as markers of apoptosis, proliferation, and myofibroblastic differentiation, respectively. Cellular senescence was confirmed by senescence-associated β-galactosidase (SA-β-gal) staining and P16Ink4a expression. Mitogenic response and gene expression were compared among normal fibroblasts, H2O2-induced senescent fibroblasts, and TGF-β-induced myofibroblasts in vitro. The senescence was further detected in mouse models of corneal scarring, alkali burn, and penetrating keratoplasty (PKP). The apoptosis and proliferation of corneal stromal cells were found to peak at 4 and 24 hours after epithelial debridement. Positive staining of SA-β-gal was observed clearly in the anterior stromal cells at 3 to 5 days. The senescent cells displayed P16Ink4a+ vimentin+ α-SMA+, representing the major origin of activated corneal resident fibroblasts. Compared with normal fibroblasts and TGF-β-induced myofibroblasts, H2O2-induced senescent fibroblasts showed a nonfibrogenic phenotype, including a reduced response to growth factor basic fibroblast growth factor (bFGF) or platelet-derived growth factor-BB (PDGF-BB), increased matrix metalloproteinase (MMP)1/3/13 expression, and decreased fibronectin and collagen I expression. Moreover, cellular senescence was commonly found in the mouse corneal scarring, alkali burn, and PKP models. Corneal epithelial debridement induced the senescence of corneal fibroblasts after apoptosis and proliferation. The senescent cells displayed a nonfibrogenic phenotype and may be involved in the self-limitation of corneal fibrosis.

"Basal Cell Migration" in Regeneration of the Corneal Wound-Bed.

In this issue of Stem Cell Reports, Park et al. (2019) describe real-time in vivo visual monitoring of keratin-14+, Confetti-labeled limbal epithelial stem cells and their progeny as they contribute to central corneal wound-healing. The authors show that corneal wounds initially heal by “basal epithelial cell migration” into the wound-bed.

Use of commercially available sodium hyaluronate 0.18% eye drops for corneal epithelial healing in diabetic patients.

To evaluate the effect of topical sodium hyaluronate (SH) 0.18% treatment on corneal epithelial healing after epithelial debridement in pars plana vitrectomy in diabetic patients. This is prospective and randomized clinical trial. Our study population included 30 eyes undergoing pars plana vitrectomy that required near total corneal debridement intra-operatively for surgical view. We compared the residual wound and wound healing rate in between 3 groups: 10 diabetic eyes (DMV) on topical SH 0.18%; 10 diabetic eyes (DMC) and 10 non-diabetic eyes (NDM) not treated with topical SH 0.18%. The corneal epithelial wound was measured at 12, 24, 36, 48, 60, 72 and 120h after the vitrectomy surgery. DMC group had corneal wounds that reepithelialization significantly more slowly than in NDM and DMV groups at 12, 24, 36 and 48h (Mann-Whitney test p < 0.05). The epithelial healing rate was significantly faster at 12h in NDM and DMV group (Mann-Whitney test p < 0.05). No differences in the residual epithelial wound and wound healing were detected in between NDM and DMV groups. The mean for epithelial closure in DMC group was delayed 87.6 ± 28.31h, compared with DMV group (64.8 ± 21.31) and NDM group (56.4 ± 9.88). All groups were followed up 1month beyond completed wound closure. No recurrent corneal epithelial wound, corneal melting or corneal neovascularization was noted. Diabetic patients on SH 0.18% four times daily for epithelial defect had similar corneal wounds healing rate as non-diabetics. This treatment significantly improved corneal wound healing and accelerated complete corneal wound resurfacing in diabetic patients.

Combined Keratectomy and Localized Limbal Cauterization for Treating Lisch Epithelial Corneal Dystrophy

To present a new technique for treating Lisch epithelial corneal dystrophy (LECD) in cases of recurrence of the disease. We present a single case report of a 41-year-old man who presented to the cornea clinic with progressive loss of vision in the right eye. Slit-lamp examination showed a large white-gray whorl-like epithelial opacity connected to the limbus, which spread over the visual axis, affecting visual acuity. The left eye was uninvolved. After epithelial debridement was performed, histological analysis showed the nonkeratinized stratified flat epithelium, coalescent cytoplasmic vacuoles in some keratinocytes, and isolated cells with granular cytoplasm and small PAS negative nuclei, which confirmed the diagnosis of LECD. Despite partially successful treatment with several sequential epithelial debridements, the patient presented with confirmed recurrence of the disease soon after every treatment. Thus, focal epitheliectomy combined with localized cauterization of the limbal focus of origin was performed. Vision returned to normal, and there were no signs of recurrence at final follow-up 2 years later. Simple epitheliectomy combined with focal cauterization of the limbal focus of origin can be a simple, safe, and minimally invasive option for treatment of LECD.

Effect of Human Corneal Mesenchymal Stromal Cell-derived Exosomes on Corneal Epithelial Wound Healing.

PurposeMesenchymal stromal cells (MSCs) have been used therapeutically to modulate inflammation and promote repair. Extracellular vesicles, including exosomes, have been identified as one of the important mediators. This study investigated the effect of human corneal MSC-derived exosomes on corneal epithelial wound healing.MethodsCorneal MSCs (cMSCs) were isolated from human cadaver corneas. The secretome was collected after 72 hours and exosomes were isolated using differential ultracentrifugation. Morphology and size of exosomes were examined by electron microscopy and dynamic light scattering. Expression of CD9, CD63, and CD81 by cMSC exosomes was evaluated by western blotting. Cellular uptake of exosomes was studied using calcein-stained exosomes. The effect of exosome on wound healing was measured in vitro using a scratch assay and in vivo after 2-mm epithelial debridement wounds in mice.ResultscMSC exosomes were morphologically round and main population ranged between 40 and 100 nm in diameter. They expressed CD9, CD63, and CD81, and did not express GM130, Calnexin, and Cytochrome-C. Stained cMSC exosomes were successfully taken up by human cMSCs, human corneal epithelial cells (HCECs), and human macrophages in vitro and by corneal epithelium in vivo. In scratch assay, after 16 hours, cMSC exosome treated HCECs had 30.1% ± 14% remaining wound area compared to 72.9% ± 8% in control (P < 0.005). In vivo, after 72 hours, cMSC exosome-treated corneas had 77.5% ± 3% corneal wound healing compared to 41.6% ± 7% in the control group (P < 0.05).ConclusionsHuman cMSC exosomes can accelerate corneal epithelial wound healing, and thus, may provide a therapeutic approach for ocular surface injuries.

Soluble Fas ligand blocks destructive corneal inflammation in mouse models of corneal epithelial debridement and LPS induced keratitis

Neutrophil-mediated inflammation plays a critical role in corneal damage following injury or infection. Previous studies demonstrated that membrane-bound FasL (mFasL) induces neutrophil chemokine production. However, the extracellular domain of mFasL is normally cleaved by matrix metalloproteinases to release a soluble form of FasL (sFasL) and sFasL antagonizes mFasL-mediated chemokine production. Therefore, we hypothesized that sFasL could be used to prevent neutrophil-mediated corneal inflammation associated with injury and bacterial keratitis. To test this hypothesis, GFP-only, sFasL-GFP, or mFasL-GFP were expressed in the corneal stroma of C57BL/6 mice, using intra-stromal injections of plasmid DNA or adenoviral vectors (AV) and the role of mFasL and sFasL in corneal inflammation was examined in models of corneal injury and LPS-induced keratitis. Our work addresses an important area of disagreement in the field of FasL, with regard to the mechanism by which sFasL regulates ocular inflammation. Herein, we demonstrate that an intrastromal injection of GFP-only, sFasL-GFP, or mFasL-GFP plasmid DNA resulted in GFP expression throughout the corneal stroma for up to two weeks with little to no evidence of inflammation in the GFP-only and sFasL-GFP groups and mild corneal inflammation in the mFasL-GFP group. Similarly, following epithelial debridement, corneas expressing GFP-only or sFasL-GFP showed no significant signs of corneal inflammation, with clear corneas at 15 days post debridement. By contrast, epithelial debridement of corneas expressing mFasL-GFP triggered persistent corneal inflammation and the development of central corneal opacities that was blocked by sFasL. Similar to the mFasL-GFP plasmid DNA, intrastromal injection of mFasL-GFP AV triggered mild corneal inflammation, but it was transient and resolved by day 10 with corneas remaining clear out to 30 days post injection. Nevertheless, intrastromal expression of mFasL-GFP AV exacerbated LPS-induced keratitis, corneal opacity, and neovascularization, while sFasL-GFP AV expression prevented LPS-induced keratitis, resulting in a clear cornea. Histological analysis of corneas with LPS-induced keratitis revealed a robust infiltration of macrophages and neutrophils and sFasL expression specifically blocked the neutrophil influx. Overall, our data demonstrate that stromal expression of mFasL is inflammatory, while sFasL is non-inflammatory, and opposes the effects of mFasL in mouse models of epithelial debridement and LPS-induced keratitis. These data demonstrate that a delicate balance between sFasL and mFasL regulates ocular inflammation. This study further identifies sFasL as a potent inhibitor of neutrophil-mediated corneal damage, and supports the potential use of sFasL in the treatment of neutrophil-mediated keratitis. These results strongly support the hypothesis that, in the immune privileged environment of the eye, the isoform of FasL regulates immune privilege and determines the extent of inflammation: mFasL promotes inflammation and sFasL blocks inflammation.

Clinical trial of adjunctive autologous platelet-rich plasma treatment following diamond-burr debridement for spontaneous chronic corneal epithelial defects in dogs.

OBJECTIVE To evaluate the effects of adjunctive treatment with autologous platelet-rich plasma (PRP) on corneal reepithelialization, vascularization, and fibrosis in dogs with spontaneous chronic corneal epithelial defects (SCCEDs). DESIGN Randomized, controlled, double-masked clinical trial. ANIMALS 40 client-owned dogs with uncomplicated SCCEDs. PROCEDURES All dogs were treated with diamond-burr epithelial debridement (DBD) of affected eyes, topical tobramycin solution and atropine sulfate ointment application, and Elizabethan collar placement for 4 weeks. Dogs were randomly assigned to topical ocular administration of autologous PRP (n = 20) or artificial tear solution (control group; 20) 4 times daily for 28 days. Recheck examinations were performed approximately 2 and 4 weeks after treatment began to evaluate SCCEDs for corneal reepithelialization, and semiquantitative corneal vascularization and corneal fibrosis scores were assigned according to affected corneal surface area. Results were compared between groups. RESULTS All dogs completed the study. The SCCEDs had completely reepithelialized in 11 (55%) control dogs and 12 (60%) PRP-treated dogs by the 2-week reevaluation, and in 15 (75%) control dogs and 18 (90%) PRP-treated dogs by the 4-week reevaluation. No significant differences were identified between groups in these proportions nor in mean differences from pretreatment scores for corneal vascularization and fibrosis. CONCLUSIONS AND CLINICAL RELEVANCE In this preliminary study involving dogs with uncomplicated SCCEDs, topical PRP administered as an adjunctive treatment following DBD had no significant effect on healing. A larger study is warranted to support or refute these findings and to determine the effects of adjunctive PRP treatment for dogs with complicated SCCEDs.

Potentiality of microemulsion systems in treatment of ophthalmic disorders: Keratoconus and dry eye syndrome - In vivo study.

Microemulsions are widely studied as potential ocular drug delivery vehicles. In the present study we show the versatility of possible use microemulsions as ocular delivery vehicle. The ME is loaded with a hydrophilic drug, riboflavin phosphate (RFP) and a lipophilic, docosahexaenoic acid in triglyceride form (TG-DHA), each separately. These drugs treat keratoconus and dry eye syndrome, respectively. The advantage of using ME loaded with RFP is in overcoming eye epithelium debridement during collagen cross-linking therapy for treatment of keratoconus. ME loaded with lipophilic TG-DHA provides convenient dosage in liquid aqueous form of administration of highly lipophilic TG-DHA, which is known as a protective molecule in dry eye syndrome. The capability of RFP-loaded MEs was demonstrated in terms of improvement of biomechanical strength of the rabbit cornea, as a result of successful penetration of RFP through the intact epithelium. TG-DHA-loaded microemulsion applied topically onto an eye with induced dry eye syndrome showed the significant relief of the dry eye condition.

Amyloid Beta Deposition Could Cause Corneal Epithelial Cell Degeneration Associated with Increasing Apoptosis in APPswePS1 Transgenic Mice

ABSTRACTObjective: To investigate the expression of amyloid precursor protein (APP) and amyloid beta (Aβ) in cornea and further explore the pathological and ultrastructural changes in corneal epithelium in APPswePS1 transgenic mice.Methods: Twelve wild type mice were grouped into control group and twelve TgAPPswePS1 mice at least 8 months old were grouped into the young experiment group (Tg-8M group), and another twelve transgenic mice at least 15 months old were selected into the aged experiment group (Tg-15M group). The pathological degeneration, ultrastructural changes, and the expression of APP, Aβ deposition, and the TUNEL reaction in corneal epithelial cells were observed. Western blot analysis was performed to determine expression levels of APP and Aβ with scraped epithelial debridement. All the results were quantified and analyzed.Results: In transgenic mice, the H&E-stained cornea sections demonstrated histopathological changes in corneal epithelial cells with irregular arrangement and the number of cell layers decreased, while normal structure observed in controls. In Tg-15M group, the corneal epithelial cell displaced a significant number of intracellular vacuoles with 1–2 cell layers left. Transmission electron microscopy (TEM) further confirmed the dramatic degeneration in corneal epithelium, the microvilli suffered degenerative changes and found with typical fingerpoint-like morphology in controls; however, microspike-like in Tg-15M group, and the number of microvilli decreased considerabely. An APP-positive immunoreaction was detected with a diffuse pattern in the corneal epithelial cells layer, about 3.122 ± 0.596 and 7.372 ± 0.936 fold changes in Tg-8M and Tg-15M groups, respectively, as compared with controls. On corneal flatmount, Aβ deposition found a diffuse pattern in the cytoplasm by fluorescence staining in TgAPPswePS1 with significantly increasing as compared with the controls, but no plaque was found. The apoptosis of TUNEL cells were observed in TgAPPswePS1 mice and increased 16.329 ± 3.542 fold changes in Tg-15M group as compared with controls.Conclusion: The APP expression and Aβ deposition might cause cornea epithelial cells degeneration in TgAPPswePS1 mice, associated with apoptosis in basal lamina cells.

Sulforaphane protects rabbit corneas against oxidative stress injury in keratoconus through activation of the Nrf-2/HO-1 antioxidant pathway.

The aim of the present study was to examine whether activation of the nuclear factor E2-related factor 2 (Nrf-2)/heme oxygenase-1 (HO-1) antioxidant pathway in the cornea was involved in the protective effect of sulforaphane (SF) following keratoconus (KC) injury. Following epithelial debridement, collagenase type II was applied in KC groups at room temperature for 30 min. Following this, rabbits were administered with a subconjunctival (s.c.) injection of SF or placebo (maize oil) daily for a total of 2 weeks. To investigate whether HO-1 was involved in the Nrf-2-related antioxidant pathway, rabbits were injected with zinc (II) protoporphyrin IX (ZnPP IX, s.c.) treatment in combination with SF 24 h following the application of collagenase type II. The protective effects of SF were evaluated by examining the mean keratometry (Km) and central cornea thickness (CCT), measuring reactive oxygen species (ROS) production using immunofluorescent staining, and analyzing the protein expression of NADPH oxidase (Nox) family members Nox-2 and Nox-4, and Nrf-2 and HO-1 using immunohistochemistry and western blot analysis. The mRNA levels of Nox-2, Nox-4, Nrf-2 and HO-1 were quantitatively detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis. No significant difference in Km or CCT was observed among groups prior to surgery (P=0.700 and P=0.982, respectively). KC induced an apparent increase of ROS generation, and caused a significant increase in Km and a significant decrease in CCT. These changes were neutralized or reversed by SF treatment. Simultaneously, SF treatment decreased the expression of Nox-2 and Nox-4, and enhanced the expression of Nrf-2 and HO-1 in the KC corneas. The RT-qPCR results indicated that SF induced downregulation of the mRNA expression of Nox-2 and Nox-4, and upregulation of the mRNA expression of Nrf-2 and HO-1 following KC injury. The HO-1 inhibitor, ZnPP IX, counteracted the protective effects of SF on KC corneas. Therefore, the present study provided evidence that activation of the Nrf-2/HO-1 signal transduction pathway may partially promote the protective effect of the antioxidant SF in the KC cornea.

Corneal Collagen Cross-Linking With Riboflavin and UVA Regulates Hemangiogenesis and Lymphangiogenesis in Rats

The purpose of this study was to determine whether corneal collagen crosslinking (CXL) inhibits hemangiogenesis and lymphangiogenesis during acute corneal inflammation in an in vivo rat model. Inflammatory corneal neovascularization was induced by suture placement into a rat cornea. At day 3 after suture, a CXL protocol using riboflavin and UVA was administered after mechanical epithelial debridement. Hemangiogenesis and lymphangiogenesis were analyzed morphometrically. CD45 and CD68 immunostaining evaluated corneal leucocyte and macrophage immune cell infiltration, respectively. A TUNEL assay detected stromal cell apoptosis. Quantitative RT-PCR analysis identified angiogenic and lymphangiogenic genes as well as proinflammatory cytokine expression. Western blot analysis characterized vascular endothelial cell CD31 and lymphatic vessel endothelial hyaluronan receptor (LYVE-1) protein expression. CXL treatment significantly reduced corneal pathologic suture-induced hemangiogenesis and lymphangiogenesis 7 days after suture emplacement, but this procedure failed to affect hemangiogenesis and lymphangiogenesis 14 days after suture. Increased cell apoptosis and reduced CD45+ and CD68+ cell infiltration were evident in CXL-treated rats on days 7 and 14 after suture emplacement. CXL treatment significantly decreased angiogenic and lymphangiogenic mRNA expression levels and both CD31 and LYVE-1 protein expression levels, whereas it increased proinflammatory cytokine levels on day 7 after suture emplacement. However, on day 14 after corneal neovascularization, angiogenic and lymphangiogenic mRNA gene expression levels were upregulated along with hematic CD31 and lymphatic LYVE-1 protein expression. CXL treatment only temporarily inhibits corneal inflammatory-associated hemangiogenesis and lymphangiogenesis in vivo. Such insight suggests that future studies are warranted to develop novel CXL strategies with longer-lasting effectiveness in attenuating hemantic- and lymphatic-related corneal diseases.

Effect of ethanol pretreatment in Acanthamoeba keratitis: a long-term follow-up study.

PurposeThe aim of this study was to evaluate the long-term outcomes of ethanol pretreatment in Acanthamoeba keratitis (AK).Patients and methodsThis single-center, retrospective, interventional study included 22 patients (24 eyes) who developed AK and underwent ethanol pretreatment between 2009 and 2015. Samples for smears, polymerase chain reaction, and culture for evidence of Acanthamoeba were collected. After ethanol pretreatment, the patients were treated with corneal epithelial debridement, topical 0.02% polyhexamethylene biguanide, and 0.1% propamidine isethionate. The primary outcomes were a clinically stable ocular surface, complete recovery from corneal infection, and acceptable corneal haze. The secondary outcome measure was improvement in best-corrected visual acuity. Complications and predictors of the visual outcome were also recorded.ResultsEthanol pretreatment was successful in 20 (83.3%) of the 24 eyes, and no further optical keratoplasty was required. Four eyes required rescue therapeutic keratoplasty because of rapid progression of AK. Patients in whom ethanol pretreatment was successful achieved good final visual outcomes regardless of sex, age, or causative Acanthamoeba species. Patients with worse initial best-corrected visual acuity and rigid gas permeable lens-related AK had better improvement in vision.ConclusionEthanol as a pretreatment for AK is safe and effective. Combined with corneal epithelial debridement, ethanol pretreatment may preclude the need for optical and therapeutic keratoplasty. This technique is suitable for all stages of AK presenting within 3 weeks of symptom onset and achieves favorable results especially in early AK.

Recurrent Corneal Erosions in Epithelial Corneal Dystrophies

The corneal epithelium is the most important structure of the ocular optical system. Recurrent corneal erosions can result from inflammation, trauma, degeneration and dystrophies. Epithelial basement membrane dystrophy (EBMD), epithelial recurrent erosion dystrophy (ERED) and Francheschetti and Meesmann's epithelial corneal dystrophy (MECD) can all - besides other signs and symptoms - result in more or less frequent corneal erosions. The pathomechanisms involved however are different. In EBMD, corneal erosions are facultative and clinical signs are often subtle. Aberrant basement membrane structures are associated with thinning of the epithelium and can be clinically identified as maps or fingerprints. In ERED, recurrent corneal erosions are - predominantly in the first decades of life - always present. A defect in the COL17A1 gene results in a dysfunctional hemidesmosome. In MECD, punctate corneal erosions are less frequent and result from intraepithelial microcysts which open spontaneously onto the ocular surface. Usually lubricants, therapeutic contact lenses and sometimes epithelial debridement and phototherapeutic keratectomy are the mainstay for treating corneal erosions in these three dystrophies.

Clinical and Histological Characterization of Toxic Keratopathy From Depatuxizumab Mafodotin (ABT-414), an Antibody-Drug Conjugate: [RETRACTED

To report the first histological characterization of microcyst-like epithelial keratopathy (MEK) associated with depatuxizumab mafodotin (ABT-414). Case report. A 35-year-old man with glioblastoma multiforme participating in a phase III trial of the antibody-drug conjugate ABT-414 developed a large corneal abrasion from complications of MEK. Confocal imaging showed multiple large, round, hyperreflective lesions. Epithelial debridement was performed. Immunohistochemistry of the diseased epithelium showed IgG-positive granular cytoplasmic inclusions and increased cell apoptosis. With discontinuation of topical steroids, frequent lubrication, bandage contact lenses, and reduction in dose to maintenance therapy, the patient experienced symptomatic improvement. However, the MEK lesions recurred after debridement. ABT-414 accumulates in the basal corneal epithelium resulting in MEK due to increased apoptosis. Frequent lubrication and bandage contact lenses can provide symptom relief.

Impact of Hyaluronic Acid-Containing Artificial Tear Products on Reepithelialization in an In Vivo Corneal Wound Model.

Purpose: To evaluate the effect of 6 commercially available hyaluronic acid (HA)-containing topical artificial tear products on corneal reepithelialization following injury, in an in vivo mouse model.Methods: Ninety-six C57Bl/6 mice (16 per treatment group; male to female ratio, 1:1 per group) were anesthetized. Epithelial debridement was performed on 1 cornea per animal, and the debrided eye was imaged. A 30 μL masked test solution containing 1 of 6 artificial tear products was instilled, immediately on debridement, and subsequently, every 2 h, for a total of 4 administrations. At 24 h post debridement, corneas were stained with fluorescein and imaged to calculate corneal healing rate (number of fluorescein-negative corneas).Results: All 6 artificial tear products used in this study permitted the initial process of corneal wound healing. However, the corneal reepithelialization rate after 24 h was higher with Hydroxypropyl guar (HPG)/HA (53.33%) compared with other HA-containing artificial tear products [HA1 (12.5%), HA2 (26.67%), HA3 (31.25%), HA4 (6.25%), and HA5 (43.75%)]. The average area and percentage area of reepithelialization after 24 h were also higher with HPG/HA compared with other treatment groups.Conclusions: Percentage of eyes with complete corneal reepithelialization 24 h post debridement was highest with HPG/HA compared with other HA-containing artificial tear products tested. The results of this study provide additional evidence on the potential benefits of HPG/HA in the management of dry eye and its role in the rapid restoration of a healthy ocular epithelium. However, further studies are required to confirm the effects on human corneal wounds.