Cornea - ARVO

ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group - Corneamice, but rarely seen in c-kit-/- mice. In wildtype mice, epithelialabrasion induced an acute inflammatory response with early (3h) andsustained (out to 30h) dilation in the limbal vessels, and significantneutrophil and platelet extravasation. Mice deficient in mast cells (ckit-/-) exhibited early vessel dilation (3h), but this response was notsustained. These mice also showed diminished platelet and neutrophilrecruitment which was accompanied by delayed (6h) epithelialwound closure and significant blunting of basal epithelial celldivision (60% less at 18h post-injury). Neutrophil recruitment waspartially restored in mast cell deficient mice that received asubconjunctival injection of cultured wildtype mast cells 4 days priorto epithelial abrasion. Experiments treating wildtype mice withcromolyn or ketotifen gave results consistent with those in c-kit -/-mice.Conclusions: Collectively, the data suggest mast cells play a pivotalrole in corneal inflammation and wound healing. Specifically, mastcells are needed for sustained limbal vessel dilation and coordinatedneutrophil and platelet recruitment. In the absence of mast cells ortheir degranulation products, the diminished leukocyte recruitmentlikely accounts for the observed reduction in the rate of cornealwound closure and the number of dividing epithelial cells.Commercial Relationships: Alan R. Burns, None; Qiong Liu,None; Zhijie Li, None; Clifton W. Smith, NoneSupport: NIH Grants EY07551, EY017120, EY018239 and NationalNatural Science Foundation of China grants 39970250, 30772387and 81070703.Program Number: 3913 Poster Board Number: D0157Presentation Time: 2:45 PM - 4:30 PMChanges in Mouse Corneal Epithelial Innervation After InjuryLanny Shulman 1 , Samuel D. Hanlon 1 , Paul T. Landry 1 , Clifton W.Smith 2 , Alan R. Burns 1, 2 . 1 College of Optometry, University ofHouston, Houston, TX; 2 Department of Leukocyte Biology, BaylorCollege of Medicine, Houston, TX.Purpose: Corneal epithelial abrasion is associated with nerve injuryand while nerve regeneration in the mouse model can occur quickly,with nerve density recovering by 6 weeks post-injury, the pattern ofthe subbasal nerve plexus is abnormal. Whether nerve regenerationinvolves a change in the number of epithelial leashes and theirdistribution is unclear. An epithelial leash is defined as a group ofsubbasal nerves originating from a deeper stromal nerve. The purposeof this study is to provide a more detailed analysis of epithelial leashnumber and distribution following a central epithelial cornealabrasion.Methods: Anesthetized adult C57BL/6 mice ages 8-10 weeksreceived 2.0 mm wide central corneal epithelial abrasions with anAlger brush. Uninjured age-matched mice served as controls. Micewere euthanized at 2, 4, and 6 weeks post-injury and corneas wereexcised, fixed and incubated in neuronal specific β-III Tubulin taggedwith phycoerythrin; DAPI staining was used to identify cell nuclei.Using a DeltaVision fluorescence microscope, corneal wholemountswere partitioned into three concentric circular zones: a central 1600μm diameter zone, a middle zone extending approximately 800 μmand a peripheral 480 μm zone. Epithelial leash number anddistribution were evaluated using Image J software and a customMatlab program.Results: In the uninjured cornea, epithelial leashes were generallyconfined to the middle (72 ±12) and peripheral zones (17 ±3); veryfew leashes were detected in the central zone (6 ±4). At 2 weeks postinjury,epithelial leash counts in the central zone increased 4-6 foldover age-matched controls and remained elevated at 4 and 6 weekspost-injury. In contrast, there was no significant change in thenumber of leashes in the middle and peripheral zones at 2, 4 or 6weeks post-injury.Conclusions: The data suggest that following a central epithelialabrasion, the greatest increase in epithelial leashes occurs in thecentral zone, which prior to injury had very few leashes. The de novoappearance of epithelial leashes in the central zone contributes to theabnormal patterning of the regenerating subbasal nerve plexus.Commercial Relationships: Lanny Shulman, None; Samuel D.Hanlon, None; Paul T. Landry, None; Clifton W. Smith, None;Alan R. Burns, NoneSupport: NH Grant EY07551; NH Grant EY017120; NH GrantEY018239411 Keratoconus and BiomechanicsWednesday, May 08, 2013 8:30 AM-10:15 AMTCC 303 Paper SessionProgram #/Board # Range: 4069-4075Organizing Section: CorneaProgram Number: 4069Presentation Time: 8:30 AM - 8:45 AMMutations in the zinc finger protein gene, ZNF469 contribute tothe pathogenesis of keratoconusAndrea L. Vincent 1, 2 , Charlotte Jordan 1, 2 , Bryan Hay 1 , Amanda J.Richards 1 , Charles N. McGhee 1, 2 . 1 Ophthalmology, New ZealandNational Eye Centre, University of Auckland, Auckland, NewZealand; 2 Eye Department, Greenlane Clinical Centre, AucklandDistrict Health Board, Auckland, New Zealand.Purpose: Mutations in the zinc finger protein gene ZNF469 areidentified as one genetic cause for the recessive disorder BrittleCornea syndrome, characterised by spontaneous corneal perforations.GWAS studies have also implicated this gene as a determinant forcentral corneal thickness(CCT). We investigated the geneticcontribution of ZNF469 in a cohort of patients with keratoconus -both familial and sporadic.Methods: Patients with keratoconus were identified and recruitedfrom the University of Auckland special eye clinic, and the EyeDepartment, Auckland District Health Board. If a family history ofkeratoconus was present, family members were recruited andexamined where possible. Following informed consent, allindividuals underwent comprehensive anterior segment examinationincluding corneal topography (Orbscan, Pentacam) and axial length,and a biological sample (venous blood, saliva) collected for DNAextraction.Mutational analysis of both exons of ZNF469 was undertaken usingpolymerase chain reaction, bidirectional Sanger sequencing, and highresolution melting analysis.4 changes detected in the familial cases (Polynesian) were screenedin an ethnically matched population. For each observed change,bioinformatic databases of exome variation were used to determinepresence and frequency, and protein prediction software to determinepathogenicity.Results: Of the 43 probands, at least one probable disease causingvariant was detected in ZNF469 in 20 (46%), and in 5, two variantswere observed (11.6% - 4 compound heterozygotes, 1 homozygote).Fourteen non-synonymous missense SNPs were observed, 6 of whichwere not previously documented in any population-based geneticvariant database. For the sporadic cases, 12/32 had one change, and3/32, 2 changes. Of the familial cases 3/11 probands had one change,and 2 of the 11 had 2 changes, although only heterozygous changessegregated with disease.Conclusions: Rare missense mutations in ZNF469, predicted to bepathogenic, are found heterozygously at a frequency of 46% in a©2013, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. 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