Publications

2018

Koo E, VanderVeen D, Lambert S. Global Practice Patterns in the Management of Infantile Cataracts. Eye Contact Lens. 2018;44 Suppl 2:S292-S296.
OBJECTIVES: Surveys are an important tool to assess the impact of research on physicians' approach to patient care. This survey was conducted to assess current practice patterns in the management of infantile cataracts in light of the findings of the Infant Aphakia Treatment Study. METHODS: Pediatric ophthalmologists were emailed a link to the survey using newsletters from American Association of Pediatric Ophthalmology and Strabismus, World Society of Pediatric Ophthalmology and Strabismus, and the Pediatric Listserv. The 17-question survey was anonymous and active during July to August 2016. RESULTS: One hundred twenty-five respondents (North America, 65%; Asia, 12%; Europe, 9%; and other, 14%) reported operating on pediatric cataracts. Most practice in a university setting (55%). There was a strong consensus that unilateral cataract surgery should be performed between ages 4 to 6 weeks and aphakic contact lenses should be used to optically correct their eyes, particularly in children ≤6 months of age. For bilateral cataracts, there was a trend for surgeons to perform cataract surgery at an older age than unilateral cataract surgery. Surgeons who performed less than 5 versus greater than 20 pediatric cataract surgeries/year were more likely to use aphakic contact lenses in children undergoing cataract surgery more than 6 months of age (62% vs. 35%, P=0.04). Most respondents (73%) indicated that the Infant Aphakia Treatment Study had changed how they manage unilateral congenital cataracts. CONCLUSION: Most pediatric cataract surgeons perform congenital cataract surgery between ages 4 to 6 weeks and use aphakic contact lenses for initial optical correction in infants less than 6 months. Surgeons have equal preference for intraocular lenses and contact lenses in infants more than 6 months of age.
Lammer J, Karst S, Lin M, Cheney M, Silva P, Burns S, Aiello LP, Sun J. Association of Microaneurysms on Adaptive Optics Scanning Laser Ophthalmoscopy With Surrounding Neuroretinal Pathology and Visual Function in Diabetes. Invest Ophthalmol Vis Sci. 2018;59(13):5633–5640.
Purpose: We evaluate diabetic microaneurysm (MA) features on high-resolution adaptive optics scanning laser ophthalmoscopy (AOSLO) and their correlations with visual acuity (VA) and local retinal pathology on spectral domain optical coherence tomography (SDOCT). Methods: Diabetic participants underwent VA testing and AOSLO and SDOCT imaging of MAs. AOSLO images were graded for MA dimension, wall hyperreflectivity (WH), intraluminal hyperreflectivity (IH), and perfusion pattern. SDOCTs centered on each MA were graded for disorganization of the retinal inner layers (DRIL) and other neuroretinal pathology. Results: We imaged 109 MAs (30 eyes). Multivariate modeling, including statistically significant covariates from bivariate analyses, associated WH with greater MA size (P = 0.001) and DRIL (P = 0.04). IH was associated with perfusion (P = 0.003) and MA visibility on photographs (P = 0.0001), and larger MA size with partial perfusion (P = 0.03), MA ring signs (P = 0.0002), and photographic visibility (P = 0.01). Multivariate modeling revealed an association of WH and VA with DRIL. Conclusions: AOSLO imaging demonstrates associations of hyperreflective MA walls with MA size and adjacent DRIL, as well as the presence of DRIL with lower VA. This study identifies a correlation between vascular and neural pathology associated with VA decline. Further studies of MA structure and neuroretinal disorganization may enable novel approaches to assess anatomic and functional outcomes in the diabetic eye.
Lopez M, Seyed-Razavi Y, Jamali A, Harris D, Hamrah P. The Chemokine Receptor CXCR4 Mediates Recruitment of CD11c+ Conventional Dendritic Cells Into the Inflamed Murine Cornea. Invest Ophthalmol Vis Sci. 2018;59(13):5671–5681.
Purpose: The cornea contains distinct populations of antigen-presenting cells (APCs), including conventional dendritic cells (cDCs). Little is known about the molecular mechanisms involved in cDCs homing and recruitment into the naïve and inflamed cornea. The purpose of this study was to investigate the presence of CXCR4 and its ligand CXCL12 in the murine cornea and its role in cDC migration during corneal inflammation. Methods: The expression of CXCR4 and CXCL12 in naïve and suture-inflamed murine corneas was assessed by whole-mount staining, flow cytometry, and quantitative PCR. The role of CXCR4 in recruitment into inflamed corneas was investigated using adoptive transfer of cDCs blocked with neutralizing antibody against CXCR4. Results: We show the chemokine receptor CXCR4 to be expressed on 51.7% and 64.8% of total corneal CD11c+ cDCs, equating to 98.6 ± 12.5 cells/mm2 in the peripheral and 64.7 ± 10.6 cells/mm2 in the central naïve cornea, respectively. Along with a 4.5-fold increase in CXCL12 expression during inflammation (P < 0.05), infiltrating cDCs also expressed CXCR4 in both the peripheral (222.6 ± 33.3 cells/mm2; P < 0.001) and central cornea (161.9 ± 23.8 cells/mm2; P = 0.001), representing a decrease to 31.0% and 37.3% in the cornea, respectively. Further, ex vivo blockade (390.1 ± 40.1 vs. 612.1 ± 78.3; P = 0.008) and local blockade (263.5 ± 27.1 vs. 807.5 ± 179.5, P < 0.001) with anti-CXCR4 neutralizing antibody resulted in a decrease in cDCs homing into the cornea compared with cells pretreated with isotype controls. Conclusions: Our results demonstrate that corneal CXCL12 plays a direct role in CXCR4+ cDC recruitment into the cornea. The CXCR4/CXCL12 axis is therefore a potential target to modulate corneal inflammatory responses.
Shen J, Xiao R, Bair J, Wang F, Vandenberghe L, Dartt D, Baranov P, Ng YSE. Novel engineered, membrane-localized variants of vascular endothelial growth factor (VEGF) protect retinal ganglion cells: a proof-of-concept study. Cell Death Dis. 2018;9(10):1018.
Endogenous vascular endothelial growth factor (VEGF-A) can protect retinal ganglion cells (RGC) from stress-induced cell death in ocular hypertensive glaucoma. To exploit the neuroprotective function of VEGF-A for therapeutic application in ocular disorders such as glaucoma while minimizing unwanted vascular side effects, we engineered two novel VEGF variants, eVEGF-38 and eVEGF-53. These variants of the diffusible VEGF-A isoform VEGF121 are expressed as dimeric concatamers and remain tethered to the cell membrane, thus restricting the effects of the engineered VEGF to the cells expressing the protein. For comparison, we tested a Myc-tagged version of VEGF189, an isoform that binds tightly to the extracellular matrix and heparan sulfate proteoglycans at the cell surface, supporting only autocrine and localized juxtacrine signaling. In human retinal endothelial cells (hREC), expression of eVEGF-38, eVEGF-53, or VEGF189 increased VEGFR2 phosphorylation without increasing expression of pro-inflammatory markers, relative to VEGF165 protein and vector controls. AAV2-mediated transduction of eVEGF-38, eVEGF-53, or VEGF189 into primary mouse RGC promoted synaptogenesis and increased the average total length of neurites and axons per RGC by ~ 12-fold, an increase that was mediated by VEGFR2 and PI3K/AKT signaling. Expression of eVEGF-38 in primary RGC enhanced expression of genes associated with neuritogenesis, axon outgrowth, axon guidance, and cell survival. Transduction of primary RGC with any of the membrane-associated VEGF constructs increased survival both under normal culture conditions and in the presence of the cytotoxic chemicals HO (via VEGFR2/PI3K/AKT signaling) and N-methyl-D-aspartate (via reduced Ca influx). Moreover, RGC number was increased in mouse embryonic stem cell-derived retinal organoid cultures transduced with the eVEGF-53 construct. The novel, engineered VEGF variants eVEGF-38 and eVEGF-53 show promise as potential therapeutics for retinal RGC neuroprotection when delivered using a gene therapy approach.
Tatematsu Y, Khan Q, Blanco T, Bair J, Hodges R, Masli S, Dartt DA. Thrombospondin-1 Is Necessary for the Development and Repair of Corneal Nerves. Int J Mol Sci. 2018;19(10).
Thrombospondin-1-deficient (TSP-1) mice are used as an animal model of Sjögren's Syndrome because they exhibit many of the symptoms associated with the autoimmune type of dry eye found in primary Sjögren's Syndrome. This type of dry eye is linked to the inflammation of the lacrimal gland, conjunctiva, and cornea, and is thought to involve dysfunction of the complex neuronal reflex arc that mediates tear production in response to noxious stimuli on the ocular surface. This study characterizes the structural and functional changes to the corneal nerves that are the afferent arm of this arc in young and older TSP-1 and wild type (WT) mice. The structure and subtype of nerves were characterized by immunohistochemistry, in vivo confocal microscopy, and confocal microscopy. Cytokine expression analysis was determined by Q-PCR and the number of monocytes was measured by immunohistochemistry. We found that only the pro-inflammatory cytokine MIP-2 increased in young corneas of TSP-1 compared to WT mice, but tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein-2 (MIP-2) all increased in older TSP-1 mouse corneas. In contrast, CD11b+ pro-inflammatory monocytes did not increase even in older mouse corneas. Calcitonin gene-related peptide (CGRP)-, but not Substance P (SubP)-containing corneal nerves decreased in older, but not younger TSP-1 compared to WT mouse corneas. We conclude that CGRP-containing corneal sensory nerves exhibit distinct structural deficiencies as disease progresses in TSP-1 mice, suggesting that: (1) TSP-1 is needed for the development or repair of these nerves and (2) impaired afferent corneal nerve structure and hence function may contribute to ocular surface dysfunction that develops as TSP-1 mice age.
Verticchio Vercellin A, Jassim F, Poon LYC, Tsikata E, Braaf B, Shah S, Ben-David G, Shieh E, Lee R, Simavli H, Que C, Papadogeorgou G, Guo R, Vakoc B, Bouma B, Boer J, Chen T. Diagnostic Capability of Three-Dimensional Macular Parameters for Glaucoma Using Optical Coherence Tomography Volume Scans. Invest Ophthalmol Vis Sci. 2018;59(12):4998–5010.
Purpose: To compare the diagnostic capability of three-dimensional (3D) macular parameters against traditional two-dimensional (2D) retinal nerve fiber layer (RNFL) thickness using spectral domain optical coherence tomography. To determine if manual correction and interpolation of B-scans improve the ability of 3D macular parameters to diagnose glaucoma. Methods: A total of 101 open angle glaucoma patients (29 with early glaucoma) and 57 healthy subjects had peripapillary 2D RNFL thickness and 3D macular volume scans. Four parameters were calculated for six different-sized annuli: total macular thickness (M-thickness), total macular volume (M-volume), ganglion cell complex (GCC) thickness, and GCC volume of the innermost 3 macular layers (retinal nerve fiber layer + ganglion cell layer + inner plexiform layer). All macular parameters were calculated with and without correction and interpolation of frames with artifacts. The areas under the receiver operating characteristic curves (AUROC) were calculated for all the parameters. Results: The 3D macular parameter with the best diagnostic performance was GCC-volume-34, with an inner diameter of 3 mm and an outer of 4 mm. The AUROC for RNFL thickness and GCC-volume-34 were statistically similar for all regions (global: RNFL thickness 0.956, GCC-volume-34 0.939, P value = 0.3827), except for the temporal GCC-volume-34, which was significantly better than temporal RNFL thickness (P value = 0.0067). Correction of artifacts did not significantly change the AUROC of macular parameters (P values between 0.8452 and 1.0000). Conclusions: The diagnostic performance of best macular parameters (GCC-volume-34 and GCC-thickness-34) were similar to or better than 2D RNFL thickness. Manual correction of artifacts with data interpolation is unnecessary in the clinical setting.
Webster A, Chintala S, Kim J, Ngan M, Itakura T, Panjwani N, Argüeso P, Barr J, Jeong S, Elizabeth Fini. Dynasore protects the ocular surface against damaging stress. PLoS One. 2018;13(10):e0204288.
Water soluble "vital" dyes are commonly used clinically to evaluate health of the ocular surface; however, staining mechanisms remain poorly understood. Recent evidence suggests that sublethal damage stimulates vital dye uptake by individual living cells. Since cell damage can also stimulate reparative plasma membrane remodeling, we hypothesized that dye uptake occurs via endocytic vesicles. In support of this idea, we show here that application of oxidative stress to relatively undifferentiated monolayer cultures of human corneal epithelial cells stimulates both dye uptake and endocytosis, and that dye uptake is blocked by co-treatment with three different endocytosis inhibitors. Stress application to stratified and differentiated corneal epithelial cell cultures, which are a better model of the ocular surface, also stimulated dye uptake; however, endocytosis was not stimulated, and two of the endocytosis inhibitors did not block dye uptake. The exception was Dynasore and its more potent analogue Dyngo-4a, both small molecules developed to target dynamin family GTPases, but also having off-target effects on the plasma membrane. Significantly, while Dynasore blocked stress-stimulated dye uptake at the ocular surface of ex vivo mouse eyes when treatment was performed at the same time as eyes were stressed, it had no effect when used after stress was applied and the ocular surface was already damaged. Thus, Dynasore could not be working by inhibiting endocytosis. Employing cytotoxicity and western blotting assays, we went on to demonstrate an alternative mechanism. We show that Dynasore is remarkably protective of cells and their surface glycocalyx, preventing damage due to stress, and thus precluding dye entry. These unexpected and novel findings provide greater insight into the mechanisms of vital dye uptake and point the direction for future study. Significantly, they also suggest that Dynasore and its analogues might be used therapeutically to protect the ocular surface and to treat ocular surface disease.
Whitman M, Nguyen E, Bell J, Tenney A, Gelber A, Engle E. Loss of CXCR4/CXCL12 Signaling Causes Oculomotor Nerve Misrouting and Development of Motor Trigeminal to Oculomotor Synkinesis. Invest Ophthalmol Vis Sci. 2018;59(12):5201–5209.
Purpose: Proper control of eye movements is critical to vision, but relatively little is known about the molecular mechanisms that regulate development and axon guidance in the ocular motor system or cause the abnormal innervation patterns (oculomotor synkinesis) seen in developmental disorders and after oculomotor nerve palsy. We developed an ex vivo slice assay that allows for live imaging and molecular manipulation of the growing oculomotor nerve, which we used to identify axon guidance cues that affect the oculomotor nerve. Methods: Ex vivo slices were generated from E10.5 IslMN-GFP embryos and grown for 24 to 72 hours. To assess for CXCR4 function, the specific inhibitor AMD3100 was added to the culture media. Cxcr4cko/cko:Isl-Cre:ISLMN-GFP and Cxcl12KO/KO:ISLMN-GFP embryos were cleared and imaged on a confocal microscope. Results: When AMD3100 was added to the slice cultures, oculomotor axons grew dorsally (away from the eye) rather than ventrally (toward the eye). Axons that had already exited the midbrain continued toward the eye. Loss of Cxcr4 or Cxcl12 in vivo caused misrouting of the oculomotor nerve dorsally and motor axons from the trigeminal motor nerve, which normally innervate the muscles of mastication, aberrantly innervated extraocular muscles in the orbit. This represents the first mouse model of trigeminal-oculomotor synkinesis. Conclusions: CXCR4/CXCL12 signaling is critical for the initial pathfinding decisions of oculomotor axons and their proper exit from the midbrain. Failure of the oculomotor nerve to innervate its extraocular muscle targets leads to aberrant innervation by other motor neurons, indicating that muscles lacking innervation may secrete cues that attract motor axons.
Yu G, Sun P, Zyl T, Tandias R, Arroyo J. BILATERAL CENTRAL RETINAL VEIN OCCLUSIONS IN A YOUNG PATIENT WITH A HISTORY OF EOSINOPHILIC PNEUMONIA AND THALAMIC STROKE. Retin Cases Brief Rep. 2018;12(4):300–304.
PURPOSE: To describe a case of a central retinal vein occlusion in a young patient with a history of eosinophilic pneumonia. METHODS: A retrospective case report of a 45-year-old woman with acute painless vision loss for 9 days after multiple episodes of eosinophilic pneumonia and thalamic stroke. Fluorescein angiography, spectral domain optical coherence tomography, and clinical examination were performed. She was then treated with intravitreal bevacizumab and pan-retinal photocoagulations. RESULTS: Retinal examination revealed tortuosity and dilatation of all branches of the central retinal vein and flame-shaped hemorrhages in all four quadrants of the right eye associated with cystoid macular edema, optic disc edema, and cotton wool spots. The left eye had mild venous dilatation and tortuosity with a few dot retinal hemorrhages in the far temporal periphery. The cystoid macular edema resolved after one intravitreal injection of bevacizumab and remained resolved at the most recent follow-up. Fluorescein angiography at the most recent follow-up revealed vasculitis in the far periphery of the nontreated eye. CONCLUSION: Central retinal vein occlusion in young patients is a rare condition often presenting as a manifestation of an underlying inflammatory or hematological disorder. Combined anti-vascular endothelial growth factor treatment and pan-retinal photocoagulation may have resolved the associated cystoid macular edema in this case, although continued observation is necessary.