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Swaminathan SS, Oh D-J, Kang MH, Ren R, Jin R, Gong H, Rhee DJ. Secreted protein acidic and rich in cysteine (SPARC)-null mice exhibit more uniform outflow. Invest Ophthalmol Vis Sci 2013;54(3):2035-47.Abstract
PURPOSE: Secreted protein acidic and rich in cysteine (SPARC) is a matricellular protein known to regulate extracellular matrix (ECM) in many tissues and is highly expressed in trabecular meshwork (TM). SPARC-null mice have a 15% to 20% decrease in intraocular pressure (IOP) compared to wild-type (WT) mice. We hypothesized that mouse aqueous outflow is segmental, and that transgenic deletion of SPARC causes a more uniform pattern that correlates with IOP and TM morphology. METHODS: Eyes of C57BL6-SV129 WT and SPARC-null mice were injected with fluorescent microbeads, which were also passively exposed to freshly enucleated eyes. Confocal and electron microscopy were performed. Percentage effective filtration length (PEFL) was calculated as PEFL = FL/TL × 100%, where TL = total length and FL = filtration length. IOP was measured by rebound tonometry. RESULTS: Passive microbead affinity for WT and SPARC-null ECM did not differ. Segmental flow was observed in the mouse eye. SPARC-null mice had a 23% decrease in IOP. PEFL increased in SPARC-null (70.61 ± 11.36%) versus WT mice (54.68 ± 9.95%, P < 0.005; n = 11 pairs), and PEFL and IOP were negatively correlated (R(2) = 0.72, n = 10 pairs). Morphologically, TM of high-tracer regions had increased separation between beams compared to low-tracer regions. Collagen fibril diameter decreased in SPARC-null (28.272 nm) versus WT tissue (34.961 nm, P < 0.0005; n = 3 pairs). CONCLUSIONS: Aqueous outflow in mice is segmental. SPARC-null mice demonstrated a more uniform outflow pattern and decreased collagen fibril diameter. Areas of high flow had less compact juxtacanalicular connective tissue ECM, and IOP was inversely correlated with PEFL. Our data show a correlation between morphology, aqueous outflow, and IOP, indicating a modulatory role of SPARC in IOP regulation.
Smith LE, Hard A-L, Hellström A. The biology of retinopathy of prematurity: how knowledge of pathogenesis guides treatment. Clin Perinatol 2013;40(2):201-14.Abstract
Retinopathy of prematurity occurs because the retina of a preterm infant at birth is incompletely vascularized, and if the postnatal environment does not match the in utero environment that supported retinal development, the vessels and neural retina will not grow normally. Risk factors determined from many clinical studies and animal studies fall into 2 categories: prenatal factors and postnatal factors.
Yoon MK, Jakobiec FA, Mendoza PR. Canaliculops: clinicopathologic features and treatment with marsupialization. Am J Ophthalmol 2013;156(5):1062-1068.e1.Abstract
PURPOSE: To report the features of the rare and under-recognized condition of canaliculops (or canaliculocele) of the eyelid, which is a dilation of the canaliculus, and to evaluate treatment with marsupialization. DESIGN: Retrospective interventional case series. METHODS: The records of 2 patients with canaliculops from the Massachusetts Eye and Ear Infirmary were reviewed. Data collected included clinical history, surgical technique, histopathologic analysis, and comparative immunohistochemical analysis of a range of cytokeratins in normal conjunctival epithelium, normal canalicular epithelium, and canaliculops epithelium. RESULTS: Two women, 53 and 66 years of age, experienced chronic, noninflammatory, painless medial eyelid and eyelid margin fluctuant swelling after earlier trauma or eyelid surgery. The external mass was accompanied by a whitish opalescent or bluish discoloration of a palpebral surface bulge. Biopsy revealed multilaminar (up to 12 cells thick), nonkeratinizing, tightly packed small squamous epithelial cells that surmounted a highly regimented basal layer with a picket fence arrangement. No goblet cells or subepithelial inflammation were present. Immunohistochemistry revealed only superficial CK7 immunostaining and positive patchy suprabasilar CK17 staining in the canaliculops epithelium, contrasting with their full-thickness positivity and negativity, respectively, in normal conjunctival epithelium. Marsupialization achieved resolution of the condition in each patient. CONCLUSIONS: An improved awareness of the normal canalicular epithelial structure and its immunohistochemical features can definitively separate canaliculops from conjunctival cysts. Previous treatment of canaliculops has involved complete excisions. Canaliculops may, however, be effectively treated with less invasive marsupialization while obtaining an adequate biopsy specimen for histopathologic diagnosis.
Yiu G, Marra KV, Wagley S, Krishnan S, Sandhu H, Kovacs K, Kuperwaser M, Arroyo JG. Surgical outcomes after epiretinal membrane peeling combined with cataract surgery. Br J Ophthalmol 2013;97(9):1197-201.Abstract
OBJECTIVE: To compare functional and anatomical outcomes after idiopathic epiretinal membrane (ERM) peeling combined with phacoemulsification and intraocular lens implantation versus ERM peeling alone. METHODS: A retrospective, non-randomised comparative case series study was conducted of 81 eyes from 79 patients who underwent ERM peeling at the Beth Israel Deaconess Medical Center between 2001 and 2010. Eyes that underwent combined surgery for ERM and cataracts (group 1) were compared with those that had ERM peeling alone (group 2) with respect to best-corrected visual acuity at 6 months and 1 year after surgery, postoperative central macular thickness (CMT) as measured on optical coherence tomography, and rates of complications, including elevated intraocular pressure (IOP), ERM recurrence and need for reoperation. RESULTS: Mean logMAR visual acuity improved significantly in both groups at 6 months (p<0.001) and 1 year (p<0.001) after surgery. There was no statistical difference between the two groups in visual acuity improvement at 6 months (p=0.108) or 1 year (p=0.094). Mean CMT of both groups also significantly decreased after surgery (p=0.002), with no statistical difference in CMT reduction between the two groups, but a trend toward less CMT reduction in group 1 (p=0.061). The rates of complications, including IOP elevation, ERM recurrence and frequency of reoperation, were similar in the two groups, with non-statistical trends toward greater ERM recurrence (p=0.084) and need for reoperation (p=0.096) in those that had combined surgery. CONCLUSIONS: Combined surgery for ERMs and cataracts may potentially be as effective as membrane peeling alone with respect to visual and anatomical outcomes. Further studies are necessary to determine if there may be greater ERM recurrence or need for reoperation after combined surgery.
Wiggs JL, Hauser MA, Abdrabou W, Allingham RR, Budenz DL, Delbono E, Friedman DS, Kang JH, Gaasterland D, Gaasterland T, Lee RK, Lichter PR, Loomis S, Liu Y, McCarty C, Medeiros FA, Moroi SE, Olson LM, Realini A, Richards JE, Rozsa FW, Schuman JS, Singh K, Stein JD, Vollrath D, Weinreb RN, Wollstein G, Yaspan BL, Yoneyama S, Zack D, Zhang K, Pericak-Vance M, Pasquale LR, Haines JL. The NEIGHBOR consortium primary open-angle glaucoma genome-wide association study: rationale, study design, and clinical variables. J Glaucoma 2013;22(7):517-25.Abstract
Primary open-angle glaucoma (POAG) is a common disease with complex inheritance. The identification of genes predisposing to POAG is an important step toward the development of novel gene-based methods of diagnosis and treatment. Genome-wide association studies (GWAS) have successfully identified genes contributing to complex traits such as POAG however, such studies frequently require very large sample sizes, and thus, collaborations and consortia have been of critical importance for the GWAS approach. In this report we describe the formation of the NEIGHBOR consortium, the harmonized case control definitions used for a POAG GWAS, the clinical features of the cases and controls, and the rationale for the GWAS study design.
Takeuchi K, Morizane Y, Kamami-Levy C, Suzuki J, Kayama M, Cai W, Miller JW, Vavvas DG. AMP-dependent kinase inhibits oxidative stress-induced caveolin-1 phosphorylation and endocytosis by suppressing the dissociation between c-Abl and Prdx1 proteins in endothelial cells. J Biol Chem 2013;288(28):20581-91.Abstract
Caveolin-1 is the primary structural component of endothelial caveolae that is essential for transcellular trafficking of albumin and is also a critical scaffolding protein that regulates the activity of signaling molecules in caveolae. Phosphorylation of caveolin-1 plays a fundamental role in the mechanism of oxidant-induced vascular hyper permeability. However, the regulatory mechanism of caveolin-1 phosphorylation remains unclear. Here we identify a previously unexpected role for AMPK in inhibition of caveolin-1 phosphorylation under oxidative stress. A pharmacological activator of AMPK, 5-amino-4-imidazole carboxamide riboside (AICAR), inhibited oxidative stress-induced phosphorylation of both caveolin-1 and c-Abl, which is the major kinase of caveolin-1, and endocytosis of albumin in human umbilical vein endothelial cell. These effects were abolished by treatment with two specific inhibitors of AICAR, dipyridamole, and 5-iodotubericidin. Consistently, knockdown of the catalytic AMPKα subunit by siRNA abolished the inhibitory effect of AICAR on oxidant-induced phosphorylation of both caveolin-1 and c-Abl. Pretreatment with specific c-Abl inhibitor, imatinib mesylate, and knock down of c-Abl significantly decreased the caveolin-1 phosphorylation after H2O2 exposure and abolished the inhibitory effect of AICAR on the caveolin-1 phosphorylation. Interestingly, knockdown of Prdx-1, an antioxidant enzyme associated with c-Abl, increased phosphorylation of both caveolin-1 and c-Abl and abolished the inhibitory effect of AICAR on the caveolin-1 phosphorylation. Furthermore, co-immunoprecipitation experiment showed that AICAR suppressed the oxidant-induced dissociation between c-Abl and Prdx1. Overall, our results suggest that activation of AMPK inhibits oxidative stress-induced caveolin-1 phosphorylation and endocytosis, and this effect is mediated in part by stabilizing the interaction between c-Abl and Prdx-1.
Stein-Streilein J. Mechanisms of immune privilege in the posterior eye. Int Rev Immunol 2013;32(1):42-56.Abstract
Immune privilege protects vital organs and their functions from the destructive interference of inflammation. Because the eye is easily accessible for surgical manipulation and for assessing and imaging the outcomes, the eye has been a major tissue for the study of immune privilege. Here, we focus on the immune regulatory mechanisms in the posterior eye, in part, because loss of immune privilege may contribute to development of certain retinal diseases in the aging population. We begin with a background in immune privilege and then focus on the select regulatory mechanisms that have been studied in the posterior eye. The review includes a description of the immunosuppressive environment, regulatory surface molecules expressed by cells in the eye, types of cells that participate in immune regulation and finally, discusses animal models of retinal laser injury in the context of mechanisms that overcome immune privilege.
Shao Z, Friedlander M, Hurst CG, Cui Z, Pei DT, Evans LP, Juan AM, Tahiri H, Tahir H, Duhamel F, Chen J, Sapieha P, Chemtob S, Joyal J-S, Smith LEH. Choroid sprouting assay: an ex vivo model of microvascular angiogenesis. PLoS One 2013;8(7):e69552.Abstract
Angiogenesis of the microvasculature is central to the etiology of many diseases including proliferative retinopathy, age-related macular degeneration and cancer. A mouse model of microvascular angiogenesis would be very valuable and enable access to a wide range of genetically manipulated tissues that closely approximate small blood vessel growth in vivo. Vascular endothelial cells cultured in vitro are widely used, however, isolating pure vascular murine endothelial cells is technically challenging. A microvascular mouse explant model that is robust, quantitative and can be reproduced without difficulty would overcome these limitations. Here we characterized and optimized for reproducibility an organotypic microvascular angiogenesis mouse and rat model from the choroid, a microvascular bed in the posterior of eye. The choroidal tissues from C57BL/6J and 129S6/SvEvTac mice and Sprague Dawley rats were isolated and incubated in Matrigel. Vascular sprouting was comparable between choroid samples obtained from different animals of the same genetic background. The sprouting area, normalized to controls, was highly reproducible between independent experiments. We developed a semi-automated macro in ImageJ software to allow for more efficient quantification of sprouting area. Isolated choroid explants responded to manipulation of the external environment while maintaining the local interactions of endothelial cells with neighboring cells, including pericytes and macrophages as evidenced by immunohistochemistry and fluorescence-activated cell sorting (FACS) analysis. This reproducible ex vivo angiogenesis assay can be used to evaluate angiogenic potential of pharmacologic compounds on microvessels and can take advantage of genetically manipulated mouse tissue for microvascular disease research.
Yoon MK, Parsa AT, Horton JC. Skull thickening, paranasal sinus expansion, and sella turcica shrinkage from chronic intracranial hypotension. J Neurosurg Pediatr 2013;11(6):667-72.Abstract
In children or young adults, the morphology of the skull can be altered by excessive drainage of CSF following placement of a ventriculoperitoneal (VP) shunt. In Sunken Eyes, Sagging Brain Syndrome, gradual enlargement of the orbital cavity occurs from low or negative intracranial pressure (ICP), leading to progressive bilateral enophthalmos. The authors report several heretofore unrecognized manifestations of this syndrome, which developed in a 29-year-old man with a history of VP shunt placement following a traumatic brain injury at the age of 9 years. Magnetic resonance imaging showed typical features of chronic intracranial hypotension, and lumbar puncture yielded an unrecordable subarachnoid opening pressure. The calvaria was twice its normal thickness, owing to contraction of the inner table. The paranasal sinuses were expanded, with aeration of the anterior clinoid processes, greater sphenoid wings, and temporal bones. The sella turcica showed a 50% reduction in cross-sectional area as compared with that in control subjects, resulting in partial extrusion of the pituitary gland. These new features broaden the spectrum of clinical findings associated with low ICP. Secondary installation of a valve to restore normal ICP is recommended to halt progression of these rare complications of VP shunt placement.
Yonekawa Y, Shildkrot Y, Eliott D. Inferior peripheral nonperfusion in bilateral diffuse uveal melanocytic proliferation. Ophthalmic Surg Lasers Imaging Retina 2013;44(2):190-2.Abstract
Bilateral diffuse uveal melanocytic proliferation (BDUMP) is a paraneoplastic syndrome characterized by cataract, photoreceptor loss and subretinal fluid overlying patchy areas of retinal pigment epithelium atrophy, and a diffusely thickened choroid with focal nodules. We present the case of a 64-year-old woman with a history of endometrial adenocarcinoma who developed BDUMP with bilateral exudative retinal detachments with inferior peripheral retinal ischemia. This new finding of peripheral nonperfusion expands the spectrum of BDUMP.
Woodward AM, Mauris J, Argüeso P. Binding of transmembrane mucins to galectin-3 limits herpesvirus 1 infection of human corneal keratinocytes. J Virol 2013;87(10):5841-7.Abstract
Epithelial cells lining mucosal surfaces impose multiple barriers to viral infection. At the ocular surface, the carbohydrate-binding protein galectin-3 maintains barrier function by cross-linking transmembrane mucins on the apical glycocalyx. Despite these defense mechanisms, many viruses have evolved to exploit fundamental cellular processes on host cells. Here, we use affinity assays to show that herpes simplex virus type 1 (HSV-1), but not HSV-2, binds human galectin-3. Knockdown of galectin-3 in human corneal keratinocytes by small interfering RNA significantly impaired HSV-1 infection, but not expression of nectin-1, indicating that galectin-3 is a herpesvirus entry mediator. Interestingly, exposure of epithelial cell cultures to transmembrane mucin isolates decreased viral infectivity. Moreover, HSV-1 failed to elute the biological counterreceptor MUC16 from galectin-3 affinity columns, suggesting that association of transmembrane mucins to galectin-3 provides protection against viral infection. Together, these results indicate that HSV-1 exploits galectin-3 to enhance virus attachment to host cells and support a protective role for transmembrane mucins under physiological conditions by masking viral entry mediators on the epithelial glycocalyx.
Walton DS, Nagao K, Yeung HH, Kane SA. Late-recognized primary congenital glaucoma. J Pediatr Ophthalmol Strabismus 2013;50(4):234-8.Abstract
PURPOSE: To describe a cohort of children with late-recognized primary congenital glaucoma (LRPCG), including age of presentation, age-related diagnostic signs, clinical abnormalities, and results of glaucoma surgery. METHODS: The medical records of 31 patients (49 eyes) with PCG recognized after 1 year of age were reviewed retrospectively. Patients were confirmed to have PCG based on their increased intraocular pressure (IOP), anterior segment abnormalities including findings on gonioscopy, and the absence of other causes of childhood glaucoma. The outcome of glaucoma surgery was reviewed and success measured by assessment of the relative control of IOP, occurrence of significant complications, and need for additional glaucoma surgery. RESULTS: Average age at diagnosis of glaucoma was 4.7 years (36% diagnosed at > 4 years of age). The most common initial diagnostic signs were corneal enlargement (46%, average age of 2.0 years), photophobia (20%, average age of 3.3 years), and suspected poor visual acuity (32%, average age of 9.9 years). Corneal cloudiness was not an initial sign for any patient. Haab's striae were present in 60% of the affected 49 eyes. Gonioscopy findings were abnormal in 82%, but the ciliary body band was seen in 81% and the scleral spur was visible in 47%. Sixty-one goniotomy procedures were performed for 39 eyes with overall success in 95% (37 eyes) and complete success in 65% (27 eyes). The final visual acuity was 20/200 or worse in 31% (15 eyes) and 20/40 or better in 60% (29 eyes). CONCLUSIONS: An awareness of and familiarity with the subtle diagnostic signs of LRPCG can enable its differentiation from primary juvenile glaucoma and contribute to earlier recognition and treatment. Glaucoma surgery is often required for LRPCG and goniosurgery is the recommended initial procedure.
Van Tyne D, Martin MJ, Gilmore MS. Structure, function, and biology of the Enterococcus faecalis cytolysin. Toxins (Basel) 2013;5(5):895-911.Abstract
Enterococcus faecalis is a Gram-positive commensal member of the gut microbiota of a wide range of organisms. With the advent of antibiotic therapy, it has emerged as a multidrug resistant, hospital-acquired pathogen. Highly virulent strains of E. faecalis express a pore-forming exotoxin, called cytolysin, which lyses both bacterial and eukaryotic cells in response to quorum signals. Originally described in the 1930s, the cytolysin is a member of a large class of lanthionine-containing bacteriocins produced by Gram-positive bacteria. While the cytolysin shares some core features with other lantibiotics, it possesses unique characteristics as well. The current understanding of cytolysin biosynthesis, structure/function relationships, and contribution to the biology of E. faecalis are reviewed, and opportunities for using emerging technologies to advance this understanding are discussed.
Sugi N, Whiston EA, Ksander BR, Gregory MS. Increased resistance to Staphylococcus aureus endophthalmitis in BALB/c mice: Fas ligand is required for resolution of inflammation but not for bacterial clearance. Infect Immun 2013;81(6):2217-25.Abstract
FasL was recently shown be required for bacterial clearance in C57BL/6 mice that express the FasL.1 allotype. The FasL.2 allotype is expressed in BALB/c mice and exhibits increased binding affinity to and increased cytotoxic activity against Fas(+) target cells. Therefore, we hypothesized that BALB/c mice would be more resistant to Staphylococcus aureus-induced endophthalmitis. To test this hypothesis, C57BL/6, BALB/c, and BALB(gld) mice received intravitreal injections of 2,500 CFU of S. aureus (RN6390). Clinical examinations, electroretinography (ERG), histology, and bacterial quantification were performed at 24, 48, 72, and 96 h postinjection. The myeloperoxidase (MPO) assay was used to quantitate neutrophil infiltration. At 96 h postinfection, 86% of C57BL/6 mice presented with complete destruction of the eye, compared to only 29% of BALB/c mice with complete destruction. To our surprise, in the absence of Fas ligand, BALB(gld) mice showed no difference in bacterial clearance compared to BALB/c mice. However, histology and ERG analysis revealed increased retinal damage and significant loss of retinal function. MPO analysis revealed equal numbers of neutrophils in BALB(gld) and BALB/c mice at 24 h postinfection. However, at 48 h, the neutrophil numbers remained significantly elevated in BALB(gld) mice, correlating with the increased retinal damage observed in BALB(gld) mice. We conclude that the increased resistance to S. aureus induced endophthalmitis in BALB/c mice is not dependent upon the FasL. However, in contrast to C57BL/6 mice, FasL is required for resolution of inflammation and protecting host tissue from nonspecific damage in BALB/c mice.

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