Cornea

Lee A, Karamichos D, Onochie OE, Hutcheon AEK, Rich CB, Zieske JD, Trinkaus-Randall V. Hypoxia modulates the development of a corneal stromal matrix model. Exp Eye Res 2018;170:127-137.Abstract
Deposition of matrix proteins during development and repair is critical to the transparency of the cornea. While many cells respond to a hypoxic state that can occur in a tumor, the cornea is exposed to hypoxia during development prior to eyelid opening and during the diurnal sleep cycle where oxygen levels can drop from 21% to 8%. In this study, we used 2 three-dimensional (3-D) models to examine how stromal cells respond to periods of acute hypoxic states. The first model, a stromal construct model, is a 3-D stroma-like construct that consists of human corneal fibroblasts (HCFs) stimulated by a stable form of ascorbate for 1, 2, and 4 weeks to self-assemble their own extracellular matrix. The second model, a corneal organ culture model, is a corneal wound-healing model, which consists of wounded adult rat corneas that were removed and placed in culture to heal. Both models were exposed to either normoxic or hypoxic conditions for varying time periods, and the expression and/or localization of matrix proteins was assessed. No significant changes were detected in Type V collagen, which is associated with Type I collagen fibrils; however, significant changes were detected in the expression of both the small leucine-rich repeating proteoglycans and the larger heparan sulfate proteoglycan, perlecan. Also, hypoxia decreased both the number of Cuprolinic blue-positive glycosaminoglycan chains along collagen fibrils and Sulfatase 1, which modulates the effect of heparan sulfate by removing the 6-O-sulfate groups. In the stromal construct model, alterations were seen in fibronectin, similar to those that occur in development and after injury. These changes in fibronectin after injury were accompanied by changes in proteoglycans. Together these findings indicate that acute hypoxic changes alter the physiology of the cornea, and these models will allow us to manipulate the conditions in the extracellular environment in order to study corneal development and trauma.
Amparo F, Shikari H, Saboo U, Dana R. Corneal fluorescein staining and ocular symptoms but not Schirmer test are useful as indicators of response to treatment in chronic ocular GVHD. Ocul Surf 2018;16(3):377-381.Abstract
PURPOSE: To evaluate long-term ocular surface clinical signs and symptoms response to therapy in patients with chronic ocular GVHD. METHODS: Retrospective review and data modeling. We reviewed the records of post-bone marrow transplantation patients who were newly diagnosed with ocular GVHD and initiated therapy, and analyzed changes in symptoms (Ocular Surface Disease Index [OSDI]; Symptom Assessment in Dry Eye [SANDE]) and signs (corneal fluorescein staining [CFS]; Schirmer test). We used a LOESS technique to fit a model in function of data variations and obtain a predictive value of the scores progression over time. RESULTS: The records of 123 patients who were followed-up for over 2 years (up to 62 months) were reviewed. The median baseline scores recorded were: OSDI 52 units, SANDE 62.2 units, CFS 2.0 Oxford units, and Schirmer 4 mm. After six months of follow up, scores improved for OSDI (-18.6 units, p = 0.007), SANDE (23.7 units, p = 0.01), and CFS (-0.7 Oxford units, p < 0.001). Data analysis showed that after a 2-year follow up the three parameters continued to improve: OSDI -13.67 units (27% reduction), SANDE -17.55 units (28%), CFS -1.1 units (54%), but Schirmer test scores progressively worsened -1.2 mm (22%). CONCLUSION: In patients with ocular GVHD symptoms and corneal fluorescein staining improved after initiation of treatment, meanwhile Schirmer scores declined progressively. This indicates that appropriate treatment in chronic ocular GVHD can lead to mid- and long-term improvements in symptoms and corneal epitheliopathy; however, sustained reduction in Schirmer test scores suggests chronic tear production impairment.
Reshef ER, Wolkow N, Jakobiec FA, Yoon MK. Histopathologic Findings of Linear Scleroderma Displaying Focal Trichiasis Secondary to Tarsal Thinning. Ophthalmic Plast Reconstr Surg 2018;34(4):e124-e127.Abstract
Linear scleroderma en coup de sabre with ophthalmic findings has been previously described in the literature on numerous occasions. A 57-year-old woman presented with focal trichiasis secondary to tarsal thinning, adjacent to a linear brow and forehead deformity consistent with linear scleroderma en coup de sabre. Cases of linear scleroderma en coup de sabre involving the eyelids have been reported, most often with madarosis, ptosis, or skin atrophy; however, to the authors' knowledge, this is the first reported case of linear scleroderma associated with trichiasis and involvement of the deeper eyelid tissues, particularly the tarsus.
Fan BJ, Chen X, Sondhi N, Sharmila FP, Soumittra N, Sripriya S, Sacikala S, Asokan R, Friedman DS, Pasquale LR, Gao RX, Vijaya L, Bailey JC, Vitart V, Macgregor S, Hammond CJ, Khor CC, Haines JL, George R, Wiggs JL, and Consortium MAGGS; IGGC; NEIGHBORHOOD. Family-Based Genome-Wide Association Study of South Indian Pedigrees Supports WNT7B as a Central Corneal Thickness Locus. Invest Ophthalmol Vis Sci 2018;59(6):2495-2502.Abstract
Purpose: To identify genetic risk factors contributing to central corneal thickness (CCT) in individuals from South India, a population with a high prevalence of ocular disorders. Methods: One hundred ninety-five individuals from 15 large South Indian pedigrees were genotyped using the Omni2.5 bead array. Family-based association for CCT was conducted using the score test in MERLIN. Results: Genome-wide association study (GWAS) identified strongest association for single nucleotide polymorphisms (SNPs) in the first intron of WNT7B and CCT (top SNP rs9330813; β = -0.57, 95% confidence interval [CI]: -0.78 to -0.36; P = 1.7 × 10-7). We further investigated rs9330813 in a Latino cohort and four independent European cohorts. A meta-analysis of these data sets demonstrated statistically significant association between rs9330813 and CCT (β = -3.94, 95% CI: -5.23 to -2.66; P = 1.7 × 10-9). WNT7B SNPs located in the same genomic region that includes rs9330813 have previously been associated with CCT in Latinos but with other ocular quantitative traits related to myopia (corneal curvature and axial length) in a Japanese population (rs10453441 and rs200329677). To evaluate the specificity of the observed WNT7B association with CCT in the South Indian families, we completed an ocular phenome-wide association study (PheWAS) for the top WNT7B SNPs using 45 ocular traits measured in these same families including corneal curvature and axial length. The ocular PheWAS results indicate that in the South Indian families WNT7B SNPs are primarily associated with CCT. Conclusions: The results indicate robust evidence for association between WNT7B SNPs and CCT in South Indian pedigrees, and suggest that WNT7B SNPs can have population-specific effects on ocular quantitative traits.
Foulsham W, Coco G, Amouzegar A, Chauhan SK, Dana R. When Clarity Is Crucial: Regulating Ocular Surface Immunity. Trends Immunol 2018;39(4):288-301.Abstract
The ocular surface is a unique mucosal immune compartment in which anatomical, physiological, and immunological features act in concert to foster a particularly tolerant microenvironment. These mechanisms are vital to the functional competence of the eye, a fact underscored by the devastating toll of excessive inflammation at the cornea - blindness. Recent data have elucidated the contributions of specific anatomical components, immune cells, and soluble immunoregulatory factors in promoting homeostasis at the ocular surface. We highlight research trends at this distinctive mucosal barrier and identify crucial gaps in our current knowledge.
O'Neil EC, Huang J, Suhler EB, Dunn JP, Perez VL, Gritz DC, McWilliams K, Peskin E, Ying G-S, Bunya VY, Maguire MG, Kempen JH. Iontophoretic delivery of dexamethasone phosphate for non-infectious, non-necrotising anterior scleritis, dose-finding clinical trial. Br J Ophthalmol 2018;102(8):1011-1013.Abstract
Currently available treatment options for non-infectious scleritis, including non-steroidal anti-inflammatory drugs, systemic corticosteroids and immunosuppressive therapies, have both efficacy and side effect limitations. Iontophoretic delivery of corticosteroids has been demonstrated to be effective for anterior uveitis and represents a potential new approach to scleritis therapy. We hypothesised that iontophoretic delivery would provide effective and precise medication delivery to the sclera, while limiting systemic exposure and side effects. This first-in-human randomised, double-masked, dose-escalating study of iontophoretic administration of dexamethasone phosphate for scleritis suggests the treatment to be well tolerated and safe (within the limitations of the 18 patients sample size). There was a suggestion of efficacy in the lowest (1.2 mA/min at 0.4 mA) dose group (corresponding to the superficial location of scleritis compared with anterior uveitis), with 5/7 eyes meeting the primary efficacy outcome within 28 days. Our results suggest iontophoretic delivery of corticosteroids is a promising potential treatment for scleritis, with favourable safety and preliminary efficacy results in this phase 1 trial. TRIAL REGISTRATION NUMBER: NCT01059955.
Gonzalez-Andrades M, Sharifi R, Islam MM, Divoux T, Haist M, Paschalis EI, Gelfand L, Mamodaly S, Di Cecilia L, Cruzat A, Ulm F-J, Chodosh J, Delori F, Dohlman CH. Improving the practicality and safety of artificial corneas: Pre-assembly and gamma-rays sterilization of the Boston Keratoprosthesis. Ocul Surf 2018;16(3):322-330.Abstract
PURPOSE: To make the Boston keratoprosthesis (B-KPro), together with its carrier corneal graft, more easily procured, transported and stored, as well as less expensive, easier for the surgeon to implant and safer for the patient, it is proposed that the B-KPro-graft combination be pre-assembled by an expert technician, followed by sterilization with gamma ray irradiation (GI) allowing long-term storage at room temperature. For this to be possible, it must be shown that the B-KPro itself (not only the graft) remains unharmed by the irradiation. METHODS: Polymethyl methacrylate (PMMA) discs and B-KPros were submitted to either ethylene oxide sterilization or different doses of GI. Cell biocompatibility, mechanical strength and optical quality were evaluated. The feasibility of assembling the B-KPro to a corneal graft, and gamma-radiate afterwards, was also assessed. RESULTS: There were no differences in cell biocompatibility between the samples. The optical evaluation showed high levels of transparency for all the groups. The absorbance of ultraviolet was higher for the groups treated with GI. The mechanical evaluation by nanoindentation showed no alterations of the PMMA discs after GI. The flexure test revealed a similar mechanical behavior. Technically, pre-assembly and GI of the B-KPro revealed no problems. CONCLUSIONS: Sterilization of B-KPro using GI has no detrimental influence on the device. The pre-assembly of B-KPro to a donor cornea, followed by gamma sterilization, emerges as an efficient and safe procedure.
Micera A, Di Zazzo A, Esposito G, Longo R, Foulsham W, Sacco R, Sgrulletta R, Bonini S. Age-Related Changes to Human Tear Composition. Invest Ophthalmol Vis Sci 2018;59(5):2024-2031.Abstract
Purpose: We characterize age-associated alterations in the expression of inflammatory mediators and tissue remodeling factors in human tears. Methods: A total of 75 consecutive volunteers (32 male/44 female; 19-93 years) underwent clinical assessment of ocular surface status, ocular surface disease index (OSDI) grading and tear sampling. The volunteers were categorized into three groups: young (18-40 years), middle-aged (41-60 years), and old (>60 years). Total protein profiles and chip-based protein array evaluations were conducted to investigate the expression of 60 potential candidates, including pro-/anti-inflammatory mediators and tissue remodeling factors. Appropriate validations were performed using conventional assays. Multiple comparisons for regression between potential candidates and age were performed, as well as statistical analyses among the three age groups. Nonpooled samples were used for quantifications. Results: Pearson analysis of chip-arrays identified 9 of 60 potential candidates. Specifically, IL-8, IL-6, and regulated on activation, normal T cell expressed and secreted (RANTES; P < 0.0083) protein as well as matrix metalloproteinase (MMP)-1, IL-3, and TNF-α (P < 0.05) correlated positively with aging. MIP-3β showed an opposite tendency. Western blot and ELISA analysis corroborated the array data. OSDI grading did not correlate with aging. Conclusions: Dynamic changes to tear protein profiles occur with aging. Our study identifies the expression of IL-8, IL-6, RANTES, MMP-1, and MIP-3β as increasing with age. These select inflammatory and matrix remodeling factors may be relevant to the development of novel diagnostic tools and therapeutics in the context of age-related ocular surface disease.
Amparo F, Dana R. Web-based longitudinal remote assessment of dry eye symptoms. Ocul Surf 2018;16(2):249-253.Abstract
PURPOSE: To investigate the feasibility of remote assessment and follow-up of dry eye symptoms using electronic versions of two validated questionnaires. METHODS: We conducted a prospective study of consecutive patients with dry eye disease (DED). Patients were enrolled during a clinical visit and were explained how to respond electronic versions of the Ocular surface Disease Index (OSDI) and the Symptom Assessment in Dry Eye (SANDE) questionnaires using a computer in the presence of investigators. A secure link to both questionnaires was sent to each patient every 2 weeks in order to respond and submit their symptoms over a 3-month period. We analyzed the number of patients who responded to both questionnaires, the recurrence, and the symptoms scores reported. RESULTS: A total of 1121 questionnaires were collected; 103 patients (85%) reported their symptoms at least once during the 3-month study duration. The majority of participants who completed the study (71.6%) responded remotely at least once per month during the 3-month duration of the study. The mean OSDI and SANDE scores from the total of remote evaluations were 34.9 ± 21.9 (range 0-97.5) and 50.3 ± 24.9 (range 0-100), respectively. There was a statistically significant correlation between the total scores collected with the two questionnaires (R = 0.67, P < 0.001). CONCLUSIONS: Patients are motivated to report DED symptoms while away from the clinic. Distance-based evaluation of DED symptoms is both feasible and convenient, and can be implemented to follow symptoms in large populations with chronic dry eye.
Xie H-T, Li J, Liu Y, Jiang D-L, Shen R-F, Zhang M-C. Cryopreserved limbal lamellar keratoplasty for peripheral corneal and limbal reconstruction. Int J Ophthalmol 2018;11(4):699-702.Abstract
This study aimed to evaluate the outcomes and described the recovery process of cryopreserved limbal lamellar keratoplasty (CLLK) for peripheral corneal and limbal diseases. Thirteen eyes of 12 patients with a mean age of 41±23.9y were included. The average follow-up was 12.1±5.6mo. Stable ocular surface was achieved in all eyes at last follow-up. Epithelialization originated from both recipient and graft in 9 eyes. We conclude that CLLK compensates for the shortage of donor corneas and cryopreserved limbal grafts provide epithelialization sources in ocular surface reconstruction.
Siatiri H, Mirzaee-Rad N, Aggarwal S, Kheirkhah A. Combined Tenonplasty and Scleral Graft for Refractory Scleritis Following Pterygium Removal with Mitomycin C Application. J Ophthalmic Vis Res 2018;13(2):200-202.Abstract
Purpose: To report a surgical approach combining scleral patch graft and tenonplasty for successful management of refractory Pseudomonas scleritis following pterygium removal with mitomycin C application. Case Report: A 75-year-old diabetic woman with a history of prior pterygium excision and mitomycin C application developed infectious necrotizing scleritis caused by . Owing to progression of scleritis despite medical management, the patient underwent surgery. Intraoperatively, extensive scleral ischemia was noted. Therefore, debridement of the necrotic tissue, scleral graft, tenonplasty to bring blood vessels to the ischemic sclera, and amniotic membrane transplantation were performed. Postoperatively, no signs of ischemia or recurrence of infection were observed. During 6 months of follow-up, the patient achieved complete restoration of the globe integrity with a non-inflamed ocular surface. Conclusion: Through restoration of blood supply to the ischemic sclera, tenonplasty is an effective adjunctive procedure in addition to conventional scleral patch graft for the treatment of refractory Pseudomonas scleritis associated with ischemia.
Paschalis EI, Lei F, Zhou C, Kapoulea V, Thanos A, Dana R, Vavvas DG, Chodosh J, Dohlman CH. The Role of Microglia and Peripheral Monocytes in Retinal Damage after Corneal Chemical Injury. Am J Pathol 2018;188(7):1580-1596.Abstract
Eyes that have experienced alkali burn to the surface are excessively susceptible to subsequent severe glaucoma and retinal ganglion cell loss, despite maximal efforts to prevent or slow down the disease. Recently, we have shown, in mice and rabbits, that such retinal damage is neither mediated by the alkali itself reaching the retina nor by intraocular pressure elevation. Rather, it is caused by the up-regulation of tumor necrosis factor-α (TNF-α), which rapidly diffuses posteriorly, causing retinal ganglion cell apoptosis and CD45 cell activation. Herein, we investigated the involvement of peripheral blood monocytes and microglia in retinal damage. Using CX3CR1::CCR2 reporter mice and bone marrow chimeras, we show that peripheral CX3CR1CD45CD11bMHC-II monocytes infiltrate into the retina from the optic nerve at 24 hours after the burn and release further TNF-α. A secondary source of peripheral monocyte response originates from a rare population of patrolling myeloid CCR2 cells of the retina that differentiate into CX3CR1 macrophages within hours after the injury. As a result, CX3CR1CD45CD11b microglia become reactive at 7 days, causing further TNF-α release. Prompt TNF-α inhibition after corneal burn suppresses monocyte infiltration and microglia activation, and protects the retina. This study may prove relevant to other injuries of the central nervous system.
Lippestad M, Hodges RR, Utheim TP, Serhan CN, Dartt DA. Signaling pathways activated by resolvin E1 to stimulate mucin secretion and increase intracellular Ca in cultured rat conjunctival goblet cells. Exp Eye Res 2018;173:64-72.Abstract
Glycoconjugate mucin secretion from conjunctival goblet cells is tightly regulated by nerves and specialized pro-resolving mediators (SPMs) to maintain ocular surface health. Here we investigated the actions of the SPM resolvin E1 (RvE1) on cultured rat conjunctival goblet cell glycoconjugate secretion and intracellular [Ca] ([Ca]) and the signaling pathways used by RvE1. Goblet cells were cultured from rat conjunctiva in RPMI medium. The amount of RvE1-stimulated glycoconjugate mucin secretion was determined using an enzyme-linked lectin assay with Ulex Europaeus Agglutinin 1 lectin. Cultured goblet cells were also incubated with the Ca indicator dye fura 2/AM and [Ca] was measured. Cultured goblet cells were incubated with inhibitors to phospholipase (PL-) C, D, and A2 signaling pathways. RvE1 stimulated glycoconjugate secretion in a concentration dependent manner and was inhibited with the Ca chelator BAPTA. The Ca response was also increased in a concentration manner when stimulated by RvE1. Inhibition of PLC, PLD, and PLA2, but not Ca/calmodulin-dependent kinase blocked RvE1-stimulated increase in [Ca] and glycoconjugate secretion. We conclude that under normal, physiological conditions RvE1 stimulates multiple pathways to increase glycoconjugate secretion and [Ca]. RvE1 could be an important regulator of goblet cell glycoconjugate mucin secretion to maintain ocular surface health.
Sahu SK, Mittal SK, Foulsham W, Li M, Sangwan VS, Chauhan SK. Mast Cells Initiate the Recruitment of Neutrophils Following Ocular Surface Injury. Invest Ophthalmol Vis Sci 2018;59(5):1732-1740.Abstract
Purpose: The purpose of this study was to investigate the contribution of mast cells to early neutrophil recruitment during ocular inflammation. Methods: In a murine model of corneal injury, the epithelium and anterior stroma were removed using a handheld motor brush. Cromolyn sodium (2% in PBS) eye drops were administered topically for mast cell inhibition. In vitro, bone marrow-derived mast cells were cultured alone or with corneal tissue. The frequencies of CD45+ inflammatory cells, CD11b+Ly6G+ neutrophils, and ckit+FcεR1+ mast cells in the cornea were assessed by flow cytometry. mRNA expression of CXCL2 was evaluated by real-time PCR and protein expression by ELISA. β-Hexosaminidase assays were performed to gauge mast cell activation. Results: Neutrophil infiltration of the cornea was observed within 1 hour of injury, with neutrophil frequencies increasing over subsequent hours. Concurrent expansion of mast cell frequencies at the cornea were observed, with mast cell activation (assessed by β-hexosaminidase levels) peaking at 6 hours after injury. Evaluation of CXCL2 mRNA and protein expression levels demonstrated augmented expression by injured corneal tissue relative to naïve corneal tissue. Mast cells were observed to constitutively express CXCL2, with significantly higher expression of CXCL2 protein compared with naïve corneal tissue. Culture with harvested injured corneas further amplified CXCL2 expression by mast cells. In vivo, mast cell inhibition was observed to decrease CXCL2 expression, limit early neutrophil infiltration, and reduce inflammatory cytokine expression by the cornea. Conclusions: Our data suggest that mast cell activation after corneal injury amplifies their secretion of CXCL2 and promotes the initiation of early neutrophil recruitment.

Pages