Concurrence of Ocular Cicatricial Pemphigoid in Chronic Ocular Graft-Versus-Host Disease.

PURPOSE: The aim of this study was to report a series of 3 patients with ocular graft-versus-host disease (oGVHD) with progressive cicatricial conjunctival changes who were diagnosed with ocular cicatricial pemphigoid (OCP) after conjunctival biopsy. METHODS: This study was a retrospective case series. RESULTS: Three patients who received hematopoietic stem cell transplantation for hematologic malignancies developed oGVHD and subsequently were diagnosed with OCP. Case 1 was a 73-year-old woman with oGVHD who developed symblepharon and showed positive IgA, IgG, and C3 staining of the basement membrane zone (BMZ) on conjunctival biopsy, consistent with OCP. She was systemically treated with tacrolimus and prednisone with resolution of conjunctival inflammation. Case 2 was a 68-year-old man with oGVHD who developed symblepharon, severe dry eye, and corneal epithelial defect. An initial conjunctival biopsy was negative, but a repeat biopsy performed 10 years later showed positive BMZ IgA and IgG staining. Healing of the epithelial defect was achieved after treatment with high-dose systemic cyclosporine. Case 3 was a 75-year-old woman with oGVHD who had a nonhealing corneal epithelial defect and symblepharon with positive IgA BMZ staining on conjunctival biopsy, consistent with OCP. The patient responded well to methotrexate with healing of the epithelial defect. CONCLUSIONS: Although low-grade conjunctival fibrotic changes may be observed in chronic oGVHD, development of severe and progressive cicatricial changes, including symblepharon formation, should prompt consideration of biopsy to rule out concurrent OCP, the management of which differs from that of oGVHD.

Epikeratophakia for Keratoconus: A Case Report with 30 Years of Follow-Up.

Background: Epikeratophakia is a refractive surgical procedure used to correct aphakic eyes, hyperopia, and keratoconus and is often performed in children. In this report, we present the long-term effects of epikeratophakia on the progression of keratoconus in a patient who underwent surgery. Case Presentation. The patient was a 17-year-old boy with keratoconus who had difficulty wearing hard contact lenses. As a solution, he underwent right eye epikeratophakia with a plano-powered lenticule. We followed up the patient for 30 years. Although the progression of keratoconus ceased in the operated eye, it continued in the nonoperated left eye and resulted in acute hydrops 9 years and 10 months after surgery. Subsequently, 20 years after the operation, anterior-segment optical coherence tomography was performed, which revealed that the progression of keratoconus had been interrupted in the right eye but had continued in the left eye, as evidenced by the parameters of the average and maximum keratometry and thinnest corneal thickness. Conclusions: Herein, we reported the longest follow-up to date of a case of keratoconus, in which one eye was treated with epikeratophakia. The progression of keratoconus was halted in the treated eye but continued in the nonoperated contralateral eye.

Investigation of the Sectorized Corneal Thickness of Eyes With Corneal Endothelial Dysfunction Using Anterior-Segment Optical Coherence Tomography.

PURPOSE: The aim of this study was to investigate the sectorized corneal thickness of eyes with corneal endothelial dysfunction using anterior-segment optical coherence tomography. METHODS: We retrospectively collected anterior-segment optical coherence tomography data conducted before endothelial keratoplasty on 53 eyes of 53 patients with corneal endothelial dysfunctions including Fuchs endothelial corneal dystrophy, bullous keratopathy (BK) after trabeculectomy, and BK after laser iridotomy and from 18 normal eyes of 18 subjects. The imaging points were divided into 17 sectors. The mean for each sector was calculated and compared with the corresponding superior/inferior and temporal/nasal sectors. RESULTS: In the normal eyes, the superior sectors were thicker than the inferior and the temporal sectors thinner than the nasal. In the diseased eyes, the superior sectors were thicker than the inferior in all subgroups; however, this tendency was no longer observed after the values were divided by the mean for the normal eyes. No significant differences were found on horizontal comparisons; however, after the values were divided by the mean for the normal eyes, the temporal sectors were thicker than the nasal. When comparing the values between the with-hole and the without-hole sides in the BK after laser iridotomy eyes, the sectors on the with-hole side were thicker than the other side. CONCLUSIONS: Corneal thickness of endothelial dysfunction was thicker in the superior sectors than the inferior but at a similar level to normal eyes. No significant differences were found for horizontal comparisons but, based on comparison with the normal eyes, the temporal sectors were thicker than the nasal.

Conventional type I migratory CD103+ dendritic cells are required for corneal allograft survival.

Corneal transplant rejection primarily occurs because of the T helper 1 (Th1) effector cell-mediated immune response of the host towards allogeneic tissue. The evidence suggests that type 1 migratory conventional CD103+ dendritic cells (CD103+DC1) acquire an immunosuppressive phenotype in the tumor environment; however, the involvement of CD103+DC1 in allograft survival continues to be an elusive question of great clinical significance in tissue transplantation. In this study, we assess the role of CD103+DC1 in suppressing Th1 alloreactivity against transplanted corneal allografts. The immunosuppressive function of CD103+DC1 has been extensively studied in non-transplantation settings. We found that host CD103+DC1 infiltrates the corneal graft and migrates to the draining lymph nodes to suppress alloreactive CD4+ Th1 cells via the programmed death-ligand 1 axis. The systemic depletion of CD103+ DC1 in allograft recipients leads to amplified Th1 activation, impaired Treg function, and increased rate of allograft rejection. Although allograft recipient Rag1 null mice reconstituted with naïve CD4+CD25- T cells efficiently generated peripheral Treg cells (pTreg), the CD103+DC1-depleted mice failed to generate pTreg. Furthermore, adoptive transfer of pTreg failed to rescue allografts in CD103+DC1-depleted recipients from rejection. These data demonstrate the critical role of CD103+DC1 in regulating host alloimmune responses.

UbiA prenyltransferase domain-containing protein 1 (UBIAD1) variant c.695 A > G identified in a multigenerational Japanese family with Schnyder corneal dystrophy.

PURPOSE: We aimed to identify pathogenic variations in the UbiA prenyltransferase domain-containing protein 1 (UBIAD1) gene in a Japanese family with Schnyder corneal dystrophy (SCD). STUDY DESIGN: Clinical study METHODS: Three clinically diagnosed SCD patients from a single pedigree participated. Patients 1 and 2 were 69- and 65-year-old sisters, and patient 3 was the 42-year-old daughter of patient 1. Blood samples from the patients were obtained for genetic analysis. Mutation screening of the two UBIAD1 exons was performed using polymerase chain reaction (PCR)-based DNA sequencing. RESULTS: All participants were found to be heterozygous for the pathogenic missense variation c.695 A > G (p.Asn232Ser) in exon 2 of UBIAD1. CONCLUSION: This is the first report on the pathogenic UBIAD1 variation c.695 A > G (p.Asn232Ser) in a Japanese population. SCD is a rare corneal dystrophy, and further research on additional cases will aid in the elucidation of disease mechanisms and development of therapeutic strategies.

Regular and irregular astigmatism of bullous keratopathy using Fourier harmonic analysis with anterior segment optical coherence tomography.

Bullous keratopathy (BK) is known to present with corneal edema and Descemet's folds, which can cause corneal astigmatism. However, no report quantitatively evaluated BK astigmatism by separating it into regular and irregular astigmatism. This study investigated the regular and irregular astigmatism of the anterior and posterior corneal surface with Fourier harmonic analysis and anterior segment optical coherence tomography. Preoperative data from 43 eyes of 41 BK patients who received corneal endothelial transplantation were compared with the data from 43 eyes of 43 subjects without corneal disease. Anterior and posterior cylinder power, central corneal thickness (CCT) and thinnest corneal thickness were significantly greater in BK. With Fourier harmonic analysis, BK eyes were found to have significantly larger anterior and posterior regular astigmatism, asymmetry component and higher-order irregularity. Asymmetry component and higher-order irregularity that accounted for the posterior irregular astigmatism increased as CCT increased in BK. Higher-order irregularity in the posterior cornea also positively correlated with worsening best corrected visual acuity. Subgroup analysis found significant correlations between CCT and posterior higher-order irregularity for intraocular surgery and laser iridotomy, but not Fuchs endothelial corneal dystrophy. This study has significance in that it revealed the characteristics of the corneal posterior irregular astigmatism of BK.

Ocular pain in ocular graft-versus-host disease patients with neurotrophic keratopathy.

PURPOSE: Neurotrophic keratopathy (NK) is a degenerative disorder of the cornea characterized by decreased sensory innervation, epitheliopathy, and impaired epithelial healing. In this study, we assessed ocular pain and quality-of-life-related parameters in ocular graft-versus-host disease (oGVHD) patients with and without NK. METHODS: We included 213 oGVHD patients in this retrospective study, including 29 patients with NK assessed by the Cochet-Bonnet esthesiometer. We evaluated their records for ocular pain assessment survey (OPAS) scores and clinical parameters, including corneal sensation, corneal fluorescein staining (CFS) score, Schirmer's test, tear break-up time (TBUT), and ocular surface disease index (OSDI) score. RESULTS: oGVHD patients with NK had lower corneal sensation (3.4 ± 1.4 vs. 5.9 ± 0.3; p < 0.0001), higher CFS scores (6.4 ± 4.2 vs. 4.7 ± 4.0; p = 0.01), and lower TBUT scores (1.2 ± 2.1 vs. 2.2 ± 3.1; p = 0.08) compared to oGVHD patients without NK and additionally had significantly higher ocular pain intensity scores (OPAS 24-h average eye pain intensity: 2.0 ± 2.8 vs. 1.1 ± 1.9; p = 0.03). Patients with NK more commonly reported burning (0.2 ± 0.3 vs. 0.3 ± 0.4; p = 0.021) and sensitivity to light (0.2 ± 0.3 vs. 0.3 ± 0.4; p = 0.049) as compared to patients without NK. CONCLUSION: Clinical signs of ocular surface disease are worse in oGVHD patients with NK compared to oGVHD patients without NK. These patients additionally experience higher intensity ocular pain and lower quality-of-life-related parameters.

Prevalence of neurotrophic keratopathy in patients with chronic ocular graft-versus-host disease.

PURPOSE: To determine the prevalence, clinical characteristics, and risk factors associated with neurotrophic keratopathy (NK) in patients with chronic ocular graft-versus-host disease (oGVHD). DESIGN: Retrospective cohort study. METHODS: We performed a chart review of patients diagnosed with chronic oGVHD between January 2015 and December 2018 at a single academic institution and recorded demographic data, systemic and ocular comorbidities, history of hematologic malignancy, transplant characteristics, oGVHD severity scores, and adnexal and ocular examination findings. We determined the prevalence of NK and clinical characteristics associated with NK in these patients. A multivariate logistic regression analysis was performed to determine the risk factors associated with NK in these patients. MAIN OUTCOME MEASURE: Prevalence of NK in chronic oGVHD. RESULTS: We identified 213 patients diagnosed with chronic oGVHD following hematopoietic stem cell or bone marrow transplantation from our electronic patient database, and the prevalence of NK was 14%. The mean age of oGVHD patients with NK was 62.6 ± 12.9 years; 48% were women, 19 had unilateral NK, and ten had bilateral NK. In the cohort, 56%, 20%, and 24% eyes of the patients had grades 1, 2, and 3 of NK, respectively. The mean time to diagnose NK after transplantation was 52.9 ± 45.4 months. oGVHD patients diagnosed with NK had a significantly higher NIH oGVHD severity score (p = 0.04) and a lower corneal sensation score (p = 0.0001) than those without NK. Our analyses showed a significantly higher CFS score (p = 0.01) and a trend toward lower Schirmer test scores (p = 0.16) and tear break-up times (p = 0.08) in oGVHD patients with NK. Additionally, we observed a significantly higher prevalence of persistent epithelial defect (p = 0.0001), corneal ulceration (p = 0.0001), and corneal perforation (p = 0.005) in oGVHD patients diagnosed with NK. A logistic regression analysis to determine factors associated with NK showed that a higher NIH oGVHD score (odds ratio [OR] = 2.03, p = 0.026) and history of cataract surgery (odds ratio [OR] = 5.03, p = 0.001) are significant risk factors for NK in oGVHD patients. CONCLUSIONS: The prevalence of NK in chronic oGVHD patients was 14% during the study period. Our analysis shows that oGVHD patients with a higher NIH oGVHD severity score and previous history of cataract surgery are at a higher risk of developing NK and may develop severe sequelae such as persistent epithelial defect or corneal ulceration.

Development and characterization of a hydrogel-based adhesive patch for sealing open-globe injuries.

Full-thickness wounds to the eye can lead to serious vision impairment. Current standards of care (from suturing to tissue transplantation) usually require highly skilled surgeons and use of an operating theater. In this study, we report the synthesis, optimization, and in vitro and ex vivo testing of photocrosslinkable hydrogel-based adhesive patches that can easily be applied to globe injuries or corneal incisions. According to the type and concentration of polymers used in the adhesive formulations, we were able to finely tune the physical properties of the bioadhesive including viscosity, elastic modulus, extensibility, ultimate tensile strength, adhesion, transparency, water content, degradation time, and swellability. Our in vitro studies showed no sign of cytotoxicity of the hydrogels. Moreover, the hydrogel patches showed higher adhesion on freshly explanted pig eyeballs compared to a marketed ocular sealant. Finally, ex vivo feasibility studies showed that the hydrogel patches could seal complex open-globe injuries such as large incision, cruciform injury, and injury associated with tissue loss. These results suggest that our photocrosslinkable hydrogel patch could represent a promising solution for the sealing of open-globe injuries or surgical incisions. STATEMENT OF SIGNIFICANCE: Current management of severe ocular injuries require advanced surgical skills and access to an operating theater. To address the need for emergent management of wounds that cannot be handled in the operating room, surgical adhesives have gained popularity, but none of the currently available adhesives have optimal bioavailability, adhesive or mechanical properties. This study describes the development, optimization and testing of a light-sensitive adhesive patch that can easily be applied to the eye. After solidification using visible light, the patch shows no toxicity and is more adherent to the tissue than a marketed sealant. Thus this technology could represent a promising solution to stabilize ocular injuries in emergency settings before definitive surgical repair.

Growth factor-eluting hydrogels for management of corneal defects.

With 1.5-2.0 million new cases annually worldwide, corneal injury represents a common cause of vision loss, often from irreversible scarring due to surface corneal defects. In this study, we assessed the use of hepatocyte growth factor (HGF) loaded into an in situ photopolymerizable transparent gelatin-based hydrogel for the management of corneal defects. In vitro release kinetics showed that, in regard to the total amount of HGF released over a month, 55 ± 11% was released during the first 24 h, followed by a slow release profile for up to one month. The effect of HGF was assessed using an ex vivo model of pig corneal defect. After three days of organ culture, epithelial defects were found to be completely healed for 89% of the corneas treated with HGF, compared to only 11% of the corneas that had fully re-epithelialized when treated with the hydrogel without HGF. The thickness of the epithelial layer was found to be significantly higher for the HGF-treated group compared to the group treated with hydrogel without HGF (p = 0.0012). Finally, histological and immunostaining assessments demonstrated a better stratification and adhesion of the epithelial layer in the presence of HGF. These results suggest that the HGF-loaded hydrogel system represents a promising solution for the treatment of persistent corneal defects at risk of scarring.

Prevalence and Risk Factors Associated With Corneal Perforation in Chronic Ocular Graft-Versus-Host-Disease.

PURPOSE: To determine the prevalence and risk factors associated with corneal perforation in patients with chronic ocular graft-versus-host disease (oGVHD). METHODS: We reviewed the case records of 405 patients diagnosed with chronic oGVHD over 8 years at a single academic center and assessed the prevalence of corneal perforation in the cohort. We reviewed patient demographics, indication for and type of hematopoietic stem cell transplantation (HSCT), time elapsed between HSCT and perforation, and clinical characteristics including oGVHD severity scores, ocular comorbidities, and topical medications at the time of perforation. Data were analyzed to determine the characteristics of patients with corneal perforation and establish the risk factors. RESULTS: Of the 405 patients with chronic oGVHD, 15 (3.7%) developed a corneal perforation. The mean age of patients at the time of perforation was 64 ± 11 years and 10 (67%) were men. The median time to corneal perforation was 3.3 years post-HSCT. Although perforation occurred unilaterally in all cases, 44% had epithelial defects and 38% had stromal abnormalities in the contralateral eye. Of the patients with corneal perforation, 9 (60%) had a National Institute of Health oGVHD severity score of 2 and 6 (40%) had a score of 3. Patients with chronic oGVHD on antiglaucoma drops had a significantly higher risk of corneal perforation (P < 0.001). CONCLUSIONS: Corneal perforation is a rare but vision-threatening complication of chronic oGVHD. Our study emphasizes the need for frequent and long-term follow-up of patients with oGVHD regardless of the severity of disease. In particular, patients with chronic oGVHD on topical antiglaucoma medications should be monitored closely due to a higher risk for corneal perforation.

Prevalence of Persistent Corneal Epithelial Defects in Chronic Ocular Graft-Versus-Host Disease.

PURPOSE: To establish the prevalence, clinical characteristics, and risk factors for persistent corneal epithelial defects (PED) in patients with chronic ocular graft-versus-host disease (oGVHD) and to determine visual outcomes after healing. DESIGN: Retrospective cohort study. METHODS: A chart review was conducted of patients in whom chronic oGVHD was diagnosed between January 2011 and December 2018 and their demographic and clinical characteristics were collected. Data were analyzed to determine prevalence of PED, and multivariate logistic regression was performed to determine the risk factors associated with it. RESULTS: A total of 405 patients at a mean age of 60 ± 13 years in whom chronic oGVHD was diagnosed; 58% were men. The prevalence of PED was 8.1%. The median time for PED development after hematopoietic stem cell transplantation was approximately 24 months. Median time to PED resolution was 4.5 weeks after starting therapy. The mean best-corrected visual acuity declined by 2 lines post-PED resolution. The prevalence rates of corneal ulcer and perforation were 6.2% and 4.0%, respectively, over 8 years. Logistic regression analysis, used to determine factors associated with PED, showed diabetes (P = .006), limbal stem cell deficiency (LSCD) (P = .02), filamentary keratitis (P = .02), subconjunctival fibrosis (P = .02), and a higher National Institutes of Health (NIH) oGVHD score (P = .01) were significant risk factors for PED development. CONCLUSIONS: The study found the prevalence rate of PED, corneal ulceration, and corneal perforation in chronic oGVHD to be 8.1%, 6.2%, and 4%, respectively. Analysis showed that oGVHD patients with diabetes, LSCD, filamentary keratitis, subconjunctival fibrosis, and a high NIH score were at higher risk of developing severe corneal disease.

Restoration of Regulatory T-Cell Function in Dry Eye Disease by Antagonizing Substance P/Neurokinin-1 Receptor.

Substance P (SP) is a tachykinin neuropeptide, implicated in the pathogenesis of various inflammatory conditions and a critical mediator in pain transmission. Recently, the role of SP was described in the pathogenesis of dry eye disease (DED) through its role in the maturation of antigen-presenting cells at the ocular surface after exposure to desiccating stress. However, the effect of SP on regulatory T cells (Tregs), which are functionally impaired in DED, remains unclear. This study examined the phenotypic and functional changes in Tregs in response to SP in DED. The in vitro cultures of normal Tregs in the presence of SP led to a significant reduction in both Treg frequencies and their suppressive function, which was prevented by the addition of an SP receptor (neurokinin-1 receptor) antagonist. Furthermore, in vivo treatment with the neurokinin-1 receptor antagonist in DED mice effectively restored Treg function, suppressed pathogenic T helper 17 response, and significantly ameliorated the disease. Our results show that a significant increase in SP levels promotes Treg dysfunction in DED, and blockade of SP effectively restores Treg function and suppresses DED severity.

Pigment Epithelium-derived Factor secreted by corneal epithelial cells regulates dendritic cell maturation in dry eye disease.

PURPOSE: In this study, we quantify Pigment Epithelium-derived Factor (PEDF) secreted by corneal epithelial cells and evaluate its immunomodulatory functions in a murine model of dry eye disease (DED). METHODS: We induced DED in female C57BL/6 mice using a controlled environment chamber for 14 days. We quantified mRNA expression of Serpinf1 gene and PEDF protein synthesis by corneal epithelial cells (CEpCs) using RT-PCR and ELISA. CEpCs from normal or DED mice were cultured with IFNγ-stimulated-dendritic cells (DCs) for 24 h, and expression of MHC-II and CD86 by DCs was determined using flow cytometry. Next, we either added recombinant PEDF (rPEDF) or anti-PEDF antibody to co-culture, and DC expression of the above maturation markers was quantified. Lastly, we treated DED mice with either topical rPEDF, anti-PEDF Ab or murine serum albumin (MSA), and DC maturation, expression of pro-inflammatory cytokines, and DED severity were investigated. RESULTS: Serpinf1 mRNA expression and PEDF protein production levels by CEpCs were upregulated in DED. CEpCs from DED mice exhibited an enhanced suppressive effect on the expression of MHC-II and CD86 by DCs, compared to normal mice. This effect was abolished by blocking endogenous PEDF with anti-PEDF Ab or enhanced by supplementing with rPEDF. Treatment with anti-PEDF antibody blocked the effect of endogenous-PEDF and increased DC maturation, expression of pro-inflammatory cytokines in conjunctivae, and exacerbated disease severity in DED mice. Conversely, topical rPEDF enhanced the suppressive effect of endogenous PEDF on DC maturation, decreased expression of pro-inflammatory cytokines in conjunctivae, and reduced disease severity. CONCLUSIONS: The results from our study elucidate the role of PEDF in impeding DC maturation, and suppression of ocular surface inflammation, explicating a promising therapeutic potential of PEDF in limiting the corneal epitheliopathy as a consequence of DED.

Aged Mice Exhibit Severe Exacerbations of Dry Eye Disease with an Amplified Memory Th17 Cell Response.

The prevalence as well as the severity of dry eye disease increase with age. Memory T helper 17 (Th17) cells (CD4+IL-17A+CD44+) drive the chronic and relapsing course of dry eye disease. Here, we investigated the contribution of memory Th17 cells to age-related dry eye disease, and evaluated memory Th17 cell depletion with anti-IL-15 antibody as a strategy to abrogate the severe exacerbations of dry eye disease observed in aged mice. After initial exposure to desiccating stress, aged mice maintained higher frequencies of memory Th17 cells in the draining lymph nodes relative to young mice. Upon secondary exposure to desiccating stress, aged mice developed more severe corneal epitheliopathy than young mice, which is associated with increased local frequencies of Th17 cells (CD4+IL-17A+). Treatment with anti-IL-15 antibody decreased the enlarged memory Th17 pool in aged mice to frequencies comparable with young mice. Furthermore, anti-IL-15-treated mice showed significantly reduced conjunctival infiltration of Th17 cells and lower corneal fluorescein staining scores compared with saline-treated control mice. Our data suggest that age-related increases in the memory Th17 compartment predispose aged mice toward the development of severe corneal epithelial disease after exposure to a dry environment. Selectively targeting memory Th17 cells may be a viable therapeutic approach in the treatment of age-related dry eye disease.

Generation of mouse model of TGFBI-R124C corneal dystrophy using CRISPR/Cas9-mediated homology-directed repair.

Mutations in transforming growth factor-beta-induced (TGFBI) gene cause clinically distinct types of corneal dystrophies. To delineate the mechanisms driving these dystrophies, we focused on the R124C mutation in TGFBI that causes lattice corneal dystrophy type1 (LCD1) and generated novel transgenic mice harbouring a single amino acid substitution of arginine 124 with cysteine in TGFBI via ssODN-mediated base-pair substitution using CRISPR/Cas9 technology. Eighty percent of homozygous and 9.1% of heterozygous TGFBI-R124C mice developed a corneal opacity at 40 weeks of age. Hematoxylin and eosin and Masson trichrome staining showed eosinophilic deposits in subepithelial corneal stroma that stained negative for Congo-red. Although amyloid deposition was not observed in TGFBI-R124C mice, irregular amorphous deposits were clearly observed via transmission electron microscopy near the basement membrane. Interestingly, we found that the corneal deposition of TGFBI protein (TGFBIp) was significantly increased in homozygous TGFBI-R124C mice, suggesting a pathogenic role for the mutant protein accumulation. Furthermore, as observed in the LCD1 patients, corneal epithelial wound healing was significantly delayed in TGFBI-R124C mice. In conclusion, our novel mouse model of TGFBI-R124C corneal dystrophy reproduces features of the human disease. This mouse model will help delineate the pathogenic mechanisms of human corneal dystrophy.

Regulatory T cells promote corneal endothelial cell survival following transplantation via interleukin-10.

The functional competence of corneal endothelial cells (CEnCs) is critical for survival of corneal allografts, but these cells are often targets of the immune response mediated by graft-attacking effector T cells. Although regulatory T cells (Tregs) have been studied for their role in regulating the host's alloimmune response towards the graft, the cytoprotective function of these cells on CEnCs has not been investigated. The aim of this study was to determine whether Tregs suppress effector T cell-mediated and inflammatory cytokine-induced CEnC death, and to elucidate the mechanism by which this cytoprotection occurs. Using 2 well-established models of corneal transplantation (low-risk and high-risk models), we show that Tregs derived from low-risk graft recipients have a superior capacity in protecting CEnCs against effector T cell-mediated and interferon-γ and tumor necrosis factor-α-induced cell death compared to Tregs derived from high-risk hosts. We further demonstrate that the cytoprotective function of Tregs derived from low-risk hosts occurs independently of direct cell-cell contact and is mediated by the immunoregulatory cytokine IL-10. Our study is the first to report that Tregs provide cytoprotection for CEnCs through secretion of IL-10, indicating potentially novel therapeutic targets for enhancing CEnC survival following corneal transplantation.

Thrombospondin-1 in ocular surface health and disease.

Thrombospondin 1 (TSP-1) is an extracellular matrix protein that interacts with a wide array of ligands including cell receptors, growth factors, cytokines and proteases to regulate various physiological and pathological processes. Constitutively expressed by certain ocular surface tissues (e.g. corneal and conjunctival epithelium), TSP-1 expression is modulated during ocular surface inflammation. TSP-1 is an important activator of latent TGF-ß, serving to promote the immunomodulatory and wound healing functions of TGF-ß. Mounting research has deepened our understanding of how TSP-1 expression (and lack thereof) contributes to ocular surface homeostasis and disease. Here, we review current knowledge of the function of TSP-1 in dry eye disease, ocular allergy, angiogenesis/lymphangiogenesis, corneal transplantation, corneal wound healing and infectious keratitis.

The purinergic receptor antagonist oxidized adenosine triphosphate suppresses immune-mediated corneal allograft rejection.

Adenosine triphosphate (ATP) is released into the extracellular environment during transplantation, and acts via purinergic receptors to amplify the alloimmune response. Here, using a well-established murine model of allogeneic corneal transplantation, we investigated the immunomodulatory mechanisms of the purinergic receptor antagonist oxidized ATP (oATP). Corneal transplantation was performed using C57BL/6 donors and BALB/c hosts. oATP or sterile saline was administered via intraperitoneal injection for 2 weeks postoperatively. Frequencies of CD45+ leukocytes, CD11b+MHCII+ antigen presenting cells (APCs), CD4+IFN-γ+ effector Th1 cells and CD4+Foxp3+ regulatory T cells (Tregs) were evaluated by flow cytometry. Slit-lamp microscopy was performed weekly for 8 weeks to evaluate graft opacity and determine transplant rejection. Treatment with oATP was shown to significantly reduce graft infiltration of CD45+ leukocytes, decrease APC maturation and suppress effector Th1 cell generation relative to saline-treated control. No difference in Treg frequencies or Foxp3 expression was observed between the oATP-treated and control groups. Finally, oATP treatment was shown to reduce graft opacity and increase graft survival. This report demonstrates that oATP limits the alloimmune response by regulating APC maturation and suppressing the generation of alloreactive Th1 immunity.

Repair of the TGFBI gene in human corneal keratocytes derived from a granular corneal dystrophy patient via CRISPR/Cas9-induced homology-directed repair.

Granular corneal dystrophy (GCD) is an autosomal dominant hereditary disease in which multiple discrete and irregularly shaped granular opacities are deposited in the corneal stroma. GCD is caused by a point mutation in the transforming growth factor-ß-induced (TGFBI) gene, located on chromosome 5q31. Here, we report the first successful application of CRISPR-Cas9-mediated genome editing for the correction of a TGFBI mutation in GCD patient-derived primary corneal keratocytes via homology-directed repair (HDR). To correct genetic defects in GCD patient cells, we designed a disease-specific guide RNA (gRNA) targeting the R124H mutation of TGFBI, which causes GCD type 2 (GCD2). An R124H mutation in primary human corneal keratocytes derived from a GCD2 patient was corrected by delivering a CRISPR plasmid expressing Cas9/gRNA and a single-stranded oligodeoxynucleotide HDR donor template in vitro. The gene correction efficiency was 20.6% in heterozygous cells and 41.3% in homozygous cells. No off-target effects were detected. These results reveal a new therapeutic strategy for GCD2; this method may also be applicable to other heredity corneal diseases.