2013

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Robinson CM, Zhou X, Rajaiya J, Yousuf MA, Singh G, DeSerres JJ, Walsh MP, Wong S, Seto D, Dyer DW, Chodosh J, Jones MS. Predicting the next eye pathogen: analysis of a novel adenovirus. MBio 2013;4(2):e00595-12.Abstract
UNLABELLED: For DNA viruses, genetic recombination, addition, and deletion represent important evolutionary mechanisms. Since these genetic alterations can lead to new, possibly severe pathogens, we applied a systems biology approach to study the pathogenicity of a novel human adenovirus with a naturally occurring deletion of the canonical penton base Arg-Gly-Asp (RGD) loop, thought to be critical to cellular entry by adenoviruses. Bioinformatic analysis revealed a new highly recombinant species D human adenovirus (HAdV-D60). A synthesis of in silico and laboratory approaches revealed a potential ocular tropism for the new virus. In vivo, inflammation induced by the virus was dramatically greater than that by adenovirus type 37, a major eye pathogen, possibly due to a novel alternate ligand, Tyr-Gly-Asp (YGD), on the penton base protein. The combination of bioinformatics and laboratory simulation may have important applications in the prediction of tissue tropism for newly discovered and emerging viruses. IMPORTANCE: The ongoing dance between a virus and its host distinctly shapes how the virus evolves. While human adenoviruses typically cause mild infections, recent reports have described newly characterized adenoviruses that cause severe, sometimes fatal human infections. Here, we report a systems biology approach to show how evolution has affected the disease potential of a recently identified novel human adenovirus. A comprehensive understanding of viral evolution and pathogenicity is essential to our capacity to foretell the potential impact on human disease for new and emerging viruses.
Robinson CM, Singh G, Lee JY, Dehghan S, Rajaiya J, Liu EB, Yousuf MA, Betensky RA, Jones MS, Dyer DW, Seto D, Chodosh J. Molecular evolution of human adenoviruses. Sci Rep 2013;3:1812.Abstract
The recent emergence of highly virulent human adenoviruses (HAdVs) with new tissue tropisms underscores the need to determine their ontogeny. Here we report complete high quality genome sequences and analyses for all the previously unsequenced HAdV serotypes (n = 20) within HAdV species D. Analysis of nucleotide sequence variability for these in conjunction with another 40 HAdV prototypes, comprising all seven HAdV species, confirmed the uniquely hypervariable regions within species. The mutation rate among HAdV-Ds was low when compared to other HAdV species. Homologous recombination was identified in at least two of five examined hypervariable regions for every virus, suggesting the evolution of HAdV-Ds has been highly dependent on homologous recombination. Patterns of alternating GC and AT rich motifs correlated well with hypervariable region recombination sites across the HAdV-D genomes, suggesting foci of DNA instability lead to formulaic patterns of homologous recombination and confer agility to adenovirus evolution.
Rose AM, Shah AZ, Alfano G, Bujakowska KM, Barker AF, Robertson LJ, Rahman S, Sánchez LV, Diaz-Corrales FJ, Chakarova CF, Krishna A, Bhattacharya SS. A Study into the Evolutionary Divergence of the Core Promoter Elements of PRPF31 and TFPT. J Mol Genet Med 2013;7(2)Abstract
Mutations in have been implicated in retinitis pigmentosa, a blinding disease caused by degeneration of rod photoreceptors. The disease mechanism in the majority of cases is haploinsufficiency. Crucially, attempts at generation of animal models of disease have proved unsuccessful, yielding animals with a visual phenotype that does not mirror human disease. This suggests that, in these animals, the transcriptional regulation of is different to humans and compared to other species. Study of the evolution of the core promoter has important implications for our understanding of human disease, as disease phenotype is modified by differentially expressed alleles in the population. lies in a head-to-head arrangement with , a gene involved in cellular apoptosis. The two genes were shown to share common regulatory elements in the human genome. In this study, the core promoters of and were characterised by dual-luciferase reporter assay using genomic DNA from the green monkey, domestic dog and house mouse. It was found that the core promoters were conserved between human and monkey. In dog, the core promoter was conserved, but different gene architecture meant the gene was controlled by a long-range promoter lying some 2000bp from the transcription start site. There was very low level of conservation (<20%) of the 5' region between mouse and human. It was shown that mouse populations did not show variable expression levels, revealing a potential explanation for the lack of phenotype observed in the knock-out mouse model.
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Sánchez J, Espinoza M, de Borba Campos M, Merabet LB. Enhancing Orientation and Mobility Skills in Learners who are Blind through Video gaming. Creat Cognit 2013;2013:353-356.Abstract
In this work we present the results of the cognitive impact evaluation regarding the use of Audiopolis, an audio and/or haptic-based videogame. The software has been designed, developed and evaluated for the purpose of developing orientation and mobility (O&M) skills in blind users. The videogame was evaluated through cognitive tasks performed by a sample of 12 learners. The results demonstrated that the use of Audiopolis had a positive impact on the development and use of O&M skills in school-aged blind learners.
Sayegh RR, Dohlman CH. Wide-angle fundus imaging through the Boston keratoprosthesis. Retina 2013;33(6):1188-92.Abstract
PURPOSE: To explore the feasibility and compare the outcomes of three wide-angle fundus cameras for imaging the peripheral retina through the Type 1 Boston keratoprosthesis. METHODS: The noncontact Optos and the contact RetCam and Panoret wide-angle imaging systems were used to image the retina of eyes implanted with a keratoprosthesis. The failure-to-image rate, ease of acquisition, and quality of the images were noted, and the field of view was compared. Limitations and complications were recorded. Optos was then performed on patients referred for ultrasound B-scan evaluation, and the imaging findings were correlated. RESULTS: Retinal images with all three cameras were obtained on four eyes. Optos could be performed on all four eyes, RetCam on three, and Panoret on two. The field of view was comparable between the three different cameras. The best quality images were obtained with Optos. The external illumination of the Panoret made it impossible to image the only darkly pigmented individual in the series. Both contact devices failed to image another patient who was too agitated. Two patients had some ocular irritation from the coupling agent that resolved with replacement of the contact lens. Optos images were obtained on an additional six eyes, and findings correlated well with those on B-scan. Optos was superior to B-scan in an eye with silicone oil filling. CONCLUSION: Wide-angle fundus imaging through the keratoprosthesis is possible, and all three cameras performed similarly. The good quality of pictures obtained with the noncontact Optos, as well as its ease of use, comfort, and safety make it a preferred choice. Optos complements B-scan in the examination of the peripheral retina through the keratoprosthesis, and it may even be superior in certain settings.
Schaumberg DA, Uchino M, Christen WG, Semba RD, Buring JE, Li JZ. Patient reported differences in dry eye disease between men and women: impact, management, and patient satisfaction. PLoS One 2013;8(9):e76121.Abstract
PURPOSE: Dry eye disease affects women twice as often as men, but there is little information on whether dry eye treatments, treatment satisfaction, or the impact of dry eye disease on patients' lives and vision might differ by sex. DESIGN: Questionnaire survey of 4000 participants in the Women's Health Study and the Physicians' Health Studies I and II with a prior report of a diagnosis of DED. METHODS: Among participants who re-confirmed a diagnosis of dry eye disease, we assessed symptoms, treatments, patient satisfaction and impact of dry eye disease, and analyzed differences between men and women using regression models. RESULTS: The final study population consisted of 1,518 women (mean age 70.7 years) and 581 men (mean age 76.7 years), with a mean reported duration of dry eye disease of 10.5 years and 10.1 years, respectively. The frequency and severity of dry eye disease symptoms were higher among women (each P<0.0001), and women reported a greater impact on everyday activities (P<0.0001). Women were more likely to use artificial tears (P<0.0001) use them more often (P<0.0001), and to use Restasis® (P<0.0001), omega-3 fatty acids (P=0.0006), and have punctal occlusion (P=0.005). Women spent more money per month on dry eye treatments (P<0.0001), but reported greater dissatisfaction with treatment side effects (P=0.001), and the amount of time before treatments started working (P=0.03). CONCLUSIONS: These data show that dry eye disease is generally experienced as being more severe among women, having a greater impact on their self-assessed well-being.
Schneider EW, Elner SG, van Kuijk FJ, Goldberg N, Lieberman RM, Eliott D, Johnson MW. Chronic retinal necrosis: cytomegalovirus necrotizing retinitis associated with panretinal vasculopathy in non-HIV patients. Retina 2013;33(9):1791-9.Abstract
PURPOSE: To characterize a unique cytomegalovirus (CMV)-associated retinopathy in patients with limited immune dysfunction. METHODS: Retrospective observational case series. CMV was confirmed as the pathogenic agent via polymerase chain reaction analysis of aqueous or vitreous humor samples or via immunohistochemical analysis of retinal biopsy specimens. RESULTS: Five non-HIV patients with granular necrotizing retinitis, vitritis, and severe occlusive vasculopathy were identified. Patient histories all suggested a basis for limited immune dysfunction including advanced age (n = 4), diabetes mellitus (n = 4), and noncytotoxic immunotherapy (n = 3). Diagnosis of CMV retinitis was delayed in all cases and patients received either no antiviral therapy (n = 2) or incorrect antiviral therapy (n = 3) for presumed herpes simplex/varicella zoster-related acute retinal necrosis. Retinitis subsequently regressed in all cases with introduction of systemic ganciclovir/valganciclovir (n = 5) and/or intravitreal foscarnet (n = 2). Four of five patients developed neovascularization because of extensive retinal ischemia. CONCLUSION: The clinical expression of CMV-associated retinopathy is strongly related to immune status. In patients with limited immune dysfunction, a mixed clinical picture of intraocular inflammation with panretinal occlusive vasculopathy, more characteristic of acute retinal necrosis, and peripheral slowly progressive granular retinitis, more characteristic of classic CMV retinitis, is observed. Recognition of this atypical clinical presentation, which the authors term chronic retinal necrosis, should prompt molecular testing for CMV to determine the appropriate antiviral therapy. Consideration should also be given to prophylactic panretinal photocoagulation in such eyes, given the high risk of neovascular complications.
Schneier AJ, Fulton AB. The hermansky-pudlak syndrome: clinical features and imperatives from an ophthalmic perspective. Semin Ophthalmol 2013;28(5-6):387-91.Abstract
The Hermansky-Pudlak Syndrome (HPS) is a rare, autosomal recessive condition comprising nine genetically heterogeneous entities that feature oculocutaneous albinism (OCA) and bleeding tendency as their principal clinical manifestations. The pathogenesis of HPS involves disturbances in the biogenesis and trafficking of lysosome-related organelles. While the ophthalmologist is trained to address the ocular manifestations of OCA, it is critical for the provider to consider HPS when examining OCA patients as its systemic sequelae may be associated with morbidity and mortality. If there is suspicion of HPS in a patient with albinism, the ophthalmologist should enlist the aid of consultants to confirm the diagnosis and monitor for systemic features. As the nine HPS subtypes explored in this article vary widely in the character and severity of their associated systemic manifestations, some authors advocate determining the specific gene defect in each HPS patient in order to optimize care and provide anticipatory guidance.
Schrems-Hoesl LM, Schrems WA, Cruzat A, Shahatit BM, Bayhan HA, Jurkunas UV, Hamrah P. Cellular and subbasal nerve alterations in early stage Fuchs' endothelial corneal dystrophy: an in vivo confocal microscopy study. Eye (Lond) 2013;27(1):42-9.Abstract
PURPOSE: To analyze the morphology and density of corneal epithelial cells, keratocytes, and subbasal nerves, in patients with early stage Fuchs' endothelial corneal dystrophy (FECD) by in vivo confocal microscopy (IVCM). METHODS: IVCM (Confoscan 4, Nidek, Inc.) of the central cornea was performed in 30 corneas of 30 patients with early stage FECD and 13 corneas of 13 normal controls. Images were analyzed for morphology and density of the superficial and basal epithelial cells, keratocyte density, endothelial cell density (ECD), as well as subbasal corneal nerve parameters. Central corneal thickness (CCT) was measured in all patients and normals by ultrasound pachymetry. RESULTS: The ECD was significantly lower (-45.5%, P<0.001) in FECD patients as compared with controls. Total number of nerves and main nerve trunks were significantly reduced (-46.3%, P<0.001; -39.7%, P<0.001) in patients with FECD. Posterior keratocyte density was significantly higher in FECD patients (P<0.001). Significant inverse correlations were found between CCT and total number of nerves (r=-0.69, P<0.001), CCT and main nerve trunks (-0.47, P=0.016), as well as CCT and total nerve length (r=-0.62, P=0.006). Significant correlation was found between ECD and total number of nerves (r=0.44, P=0.012) as well as between ECD and main nerve trunks (r=0.65, P<0.001). CONCLUSIONS: IVCM demonstrates alterations in corneal innervation in patients with early stage FECD, suggesting a potential role of corneal nerves in the pathogenesis of FECD. Additional studies are required to investigate whether subbasal nerve alterations are caused by nonspecific corneal edema, from FECD-induced decrease in ECD, or potentially leading to loss of endothelial cells.
Shaaban S, Ramos-Platt L, Gilles FH, Chan W-M, Andrews C, De Girolami U, Demer J, Engle EC. RYR1 mutations as a cause of ophthalmoplegia, facial weakness, and malignant hyperthermia. JAMA Ophthalmol 2013;131(12):1532-40.Abstract
IMPORTANCE: Total ophthalmoplegia can result from ryanodine receptor 1 (RYR1) mutations without overt associated skeletal myopathy. Patients carrying RYR1 mutations are at high risk of developing malignant hyperthermia. Ophthalmologists should be familiar with these important clinical associations. OBJECTIVE: To determine the genetic cause of congenital ptosis, ophthalmoplegia, facial paralysis, and mild hypotonia segregating in 2 pedigrees diagnosed with atypical Moebius syndrome or congenital fibrosis of the extraocular muscles. DESIGN, SETTING, AND PARTICIPANTS: Clinical data including medical and family histories were collected at research laboratories at Boston Children's Hospital and Jules Stein Eye Institute (Engle and Demer labs) for affected and unaffected family members from 2 pedigrees in which patients presented with total ophthalmoplegia, facial weakness, and myopathy. INTERVENTION: Homozygosity mapping and whole-exome sequencing were conducted to identify causative mutations in affected family members. Histories, physical examinations, and clinical data were reviewed. MAIN OUTCOME AND MEASURE: Mutations in RYR1. RESULTS: Missense mutations resulting in 2 homozygous RYR1 amino acid substitutions (E989G and R3772W) and 2 compound heterozygous RYR1 substitutions (H283R and R3772W) were identified in a consanguineous and a nonconsanguineous pedigree, respectively. Orbital magnetic resonance imaging revealed marked hypoplasia of extraocular muscles and intraorbital cranial nerves. Skeletal muscle biopsy specimens revealed nonspecific myopathic changes. Clinically, the patients' ophthalmoplegia and facial weakness were far more significant than their hypotonia and limb weakness and were accompanied by an unrecognized susceptibility to malignant hyperthermia. CONCLUSIONS AND RELEVANCE: Affected children presenting with severe congenital ophthalmoplegia and facial weakness in the setting of only mild skeletal myopathy harbored recessive mutations in RYR1, encoding the ryanodine receptor 1, and were susceptible to malignant hyperthermia. While ophthalmoplegia occurs rarely in RYR1-related myopathies, these children were atypical because they lacked significant weakness, respiratory insufficiency, or scoliosis. RYR1-associated myopathies should be included in the differential diagnosis of congenital ophthalmoplegia and facial weakness, even without clinical skeletal myopathy. These patients should also be considered susceptible to malignant hyperthermia, a life-threatening anesthetic complication avoidable if anticipated presurgically.
Shah DN, Huang J, Ying G-S, Pietrobon R, O'Brien JM. Trends in female representation in published ophthalmology literature, 2000-2009. Digit J Ophthalmol 2013;19(4):50-5.Abstract
PURPOSE: To examine trends in female first and last authors in clinical ophthalmology literature published from January 2000 to December 2009. METHODS: A total of 3760 articles in American Journal of Ophthalmology (AJO), 2347 articles in Archives of Ophthalmology (Archives), and 3838 articles in Ophthalmology spanning 10 years of published ophthalmology peer-reviewed literature were examined. All original research articles and brief reports indexed online were included. Author gender was determined by an exhaustive Internet search. Articles were excluded if the sex of the author could not be determined or was not applicable (for example, articles by a study group rather than an individual author). RESULTS: Gender information was identified in 86.8% of articles for first authors and 86% for last authors. The number of female first authors (P < 0.0001) and last authors (P = 0.005) increased significantly in the study period in all journals examined, with a significant association between the sex of the first and last authors (OR = 2.19; 95% CI, 1.96-2.46; P < 0.0001), when examining all articles. Female representation increased for last authors significantly only in Ophthalmology. There was a significant correlation between gender of the first author and total number of authors that was not observed with last-author sex. CONCLUSIONS: Female first authorship has increased from 2000 to 2009 and is correlated with the gender of the last author; however, there were fewer female last authors compared to female first authors in the same period.
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.
Silva PS, Cavallerano JD, Sun JK, Soliman AZ, Aiello LM, Aiello LP. Peripheral lesions identified by mydriatic ultrawide field imaging: distribution and potential impact on diabetic retinopathy severity. Ophthalmology 2013;120(12):2587-2595.Abstract
OBJECTIVE: To assess diabetic retinopathy (DR) as determined by lesions identified using mydriatic ultrawide field imaging (DiSLO200; Optos plc, Scotland, UK) compared with Early Treatment Diabetic Retinopathy Study (ETDRS) 7-standard field film photography. DESIGN: Prospective comparative study of DiSLO200, ETDRS 7-standard field film photographs, and dilated fundus examination (DFE). PARTICIPANTS: A total of 206 eyes of 103 diabetic patients selected to represent all levels of DR. METHODS: Subjects had DiSLO200, ETDRS 7-standard field film photographs, and DFE. Images were graded for severity and distribution of DR lesions. Discrepancies were adjudicated, and images were compared side by side. MAIN OUTCOME MEASURES: Distribution of hemorrhage and/or microaneurysm (H/Ma), venous beading (VB), intraretinal microvascular abnormality (IRMA), and new vessels elsewhere (NVE). Kappa (κ) and weighted κ statistics for agreement. RESULTS: The distribution of DR severity by ETDRS 7-standard field film photographs was no DR 12.5%; nonproliferative DR mild 22.5%, moderate 30%, and severe/very severe 8%; and proliferative DR 27%. Diabetic retinopathy severity between DiSLO200 and ETDRS film photographs matched in 80% of eyes (weighted κ = 0.74,κ = 0.84) and was within 1 level in 94.5% of eyes. DiSLO200 and DFE matched in 58.8% of eyes (weighted κ = 0.69,κ = 0.47) and were within 1 level in 91.2% of eyes. Forty eyes (20%) had DR severity discrepancies between DiSLO200 and ETDRS film photographs. The retinal lesions causing discrepancies were H/Ma 52%, IRMA 26%, NVE 17%, and VB 4%. Approximately one-third of H/Ma, IRMA, and NVE were predominantly outside ETDRS fields. Lesions identified on DiSLO200 but not ETDRS film photographs suggested a more severe DR level in 10% of eyes. Distribution in the temporal, superotemporal, inferotemporal, superonasal, and inferonasal fields was 77%, 72%, 61%, 65%, and 59% for H/Ma, respectively (P<0.0001); 22%, 24%, 21%, 28%, and 22% for VB, respectively (P = 0.009); 52%, 40%, 29%, 47%, and 36% for IRMA, respectively (P<0.0001), and 8%, 4%, 4%, 8%, and 5% for NVE, respectively (P = 0.03). All lesions were more frequent in the temporal fields compared with the nasal fields (P<0.0001). CONCLUSIONS: DiSLO200 images had substantial agreement with ETDRS film photographs and DFE in determining DR severity. On the basis of DiSLO200 images, significant nonuniform distribution of DR lesions was evident across the retina. The additional peripheral lesions identified by DiSLO200 in this cohort suggested a more severe assessment of DR in 10% of eyes than was suggested by the lesions within the ETDRS fields. However, the implications of peripheral lesions on DR progression within a specific ETDRS severity level over time are unknown and need to be evaluated prospectively.
Singh G, Robinson CM, Dehghan S, Jones MS, Dyer DW, Seto D, Chodosh J. Homologous recombination in E3 genes of human adenovirus species D. J Virol 2013;87(22):12481-8.Abstract
Genes within the E3 transcription unit of human adenoviruses modulate host immune responses to infection. A comprehensive genomics and bioinformatics analysis of the E3 transcription unit for 38 viruses within human adenovirus species D (HAdV-D) revealed distinct and surprising patterns of homologous recombination. Homologous recombination was identified in open reading frames for E3 CR1α, CR1β, and CR1γ, similar to that previously observed with genes encoding the three major structural capsid proteins, the penton base, hexon, and fiber.
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.
Spurr-Michaud SJ, Gipson IK. Methods for culture of human corneal and conjunctival epithelia. Methods Mol Biol 2013;945:31-43.Abstract
The surface of the eye is exposed to the outside world and is, thus, subject to surface abrasion, infections, and drying, cicatrizing diseases. Availability of in vitro methods for culture of the human corneal and conjunctival epithelia, which cover the ocular surface, is therefore important in understanding the biology of these epithelia and their response to disease/infections, as well as for providing human-relevant models for preclinical testing of potential therapeutic agents. The ensuing chapter describes several methods for primary culture of both corneal and conjunctival epithelia and culture of immortalized cell lines, and methods employed to induce differentiation in the cultured epithelia.
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.
Stryjewski TP, Vavvas DG. Genetic correlates of proliferative vitreoretinopathy. Invest Ophthalmol Vis Sci 2013;54(3)
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.
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.

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