April 2015

Shen J, Peli E, Bowers AR. Peripheral Prism Glasses: Effects of Moving and Stationary Backgrounds. Optom Vis Sci 2015;92(4):412-420.Abstract

PURPOSE: Unilateral peripheral prisms for homonymous hemianopia (HH) expand the visual field through peripheral binocular visual confusion, a stimulus for binocular rivalry that could lead to reduced predominance and partial suppression of the prism image, thereby limiting device functionality. Using natural-scene images and motion videos, we evaluated whether detection was reduced in binocular compared with monocular viewing. METHODS: Detection rates of nine participants with HH or quadranopia and normal binocularity wearing peripheral prisms were determined for static checkerboard perimetry targets briefly presented in the prism expansion area and the seeing hemifield. Perimetry was conducted under monocular and binocular viewing with targets presented over videos of real-world driving scenes and still frame images derived from those videos. RESULTS: With unilateral prisms, detection rates in the prism expansion area were significantly lower in binocular than in monocular (prism eye) viewing on the motion background (medians, 13 and 58%, respectively, p = 0.008) but not the still frame background (medians, 63 and 68%, p = 0.123). When the stimulus for binocular rivalry was reduced by fitting prisms bilaterally in one HH and one normally sighted subject with simulated HH, prism-area detection rates on the motion background were not significantly different (p > 0.6) in binocular and monocular viewing. CONCLUSIONS: Conflicting binocular motion appears to be a stimulus for reduced predominance of the prism image in binocular viewing when using unilateral peripheral prisms. However, the effect was only found for relatively small targets. Further testing is needed to determine the extent to which this phenomenon might affect the functionality of unilateral peripheral prisms in more real-world situations.

Stein JD, Talwar N, Kang JH, Okereke OI, Wiggs JL, Pasquale LR. Bupropion Use and Risk of Open-Angle Glaucoma among Enrollees in a Large U.S. Managed Care Network. PLoS One 2015;10(4):e0123682.Abstract

OBJECTIVE: Tumor Necrosis Factor (TNF) mediates retinal ganglion cell death in glaucoma. Anti-TNF drugs are neuroprotective in an animal model of glaucoma. It is unclear whether medications with anti-TNF properties such as bupropion have an impact on the risk of developing open-angle glaucoma (OAG) in humans. The purpose of this study is to determine whether bupropion use alters the risk of developing OAG. METHODS: Claims data for beneficiaries age ≥35 years with no pre-existing OAG enrolled in a large nationwide U.S. managed care network continuously for ≥4 years between 2001-2011 was analyzed to identify patients who had been newly-diagnosed with OAG. The amount of bupropion use as captured from outpatient pharmacy claims over a four-year period was also quantified for each beneficiary. Multivariable Cox regression modeling assessed the impact of bupropion and other antidepressant medications on the risk of developing OAG with adjustment for sociodemographic characteristics of the enrollees along with medical and ocular comorbidities. RESULTS: Of 638,481 eligible enrollees, 15,292 (2.4%) developed OAG. After adjustment for confounding factors including use of other antidepressant medication classes, each additional month of bupropion use was associated with a 0.6% reduced risk of OAG (HR = 0.994, (95% CI: 0.989-0.998), p = 0.007). Compared to nonusers, those with 24-48 months of bupropion use had a 21% reduced hazard (HR=0.79, (CI: 0.65-0.94), p = 0.0099) of OAG. This association did not differ among persons taking bupropion for depression or for other reasons (p-interaction = 0.82). There was no significant association between use of tricyclic antidepressants (HR = 1.000, (CI: 0.997-1.004), p = 0.95) or selective serotonin reuptake inhibitors (HR = 0.999, (CI: 0.997-1.001), p = 0.39) and development of OAG. CONCLUSION: These findings suggest bupropion use may be beneficial in reducing the risk of OAG. If prospective studies confirm the findings of this analysis, this may identify a novel therapeutic target for OAG.

Uchiyama E, Faez S, Nasir H, Unizony SH, Plenge R, Papaliodis GN, Sobrin L. Accuracy of the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) as a research tool for identification of patients with uveitis and scleritis. Ophthalmic Epidemiol 2015;22(2):139-41.Abstract

PURPOSE: To report on the accuracy of the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes for identifying patients with polymyalgia rheumatica (PMR) and concurrent noninfectious inflammatory ocular conditions in a large healthcare organization database. METHODS: Queries for patients with PMR and uveitis or scleritis were executed in two general teaching hospitals' databases. Patients with ocular infections or other rheumatologic conditions were excluded. Patients with PMR and ocular inflammation were identified, and medical records were reviewed to confirm accuracy. RESULTS: The query identified 10,697 patients with the ICD-9-CM code for PMR and 4154 patients with the codes for noninfectious inflammatory ocular conditions. The number of patients with both PMR and noninfectious uveitis or scleritis by ICD-9-CM codes was 66. On detailed review of the charts of these 66 patients, 31 (47%) had a clinical diagnosis of PMR, 43 (65%) had noninfectious uveitis or scleritis, and only 20 (30%) had PMR with concurrent noninfectious uveitis or scleritis confirmed based on clinical notes. CONCLUSIONS: While the use of ICD-9-CM codes has been validated for medical research of common diseases, our results suggest that ICD-9-CM codes may be of limited value for epidemiological investigations of diseases which can be more difficult to diagnose. The ICD-9-CM codes for rarer diseases (PMR, uveitis and scleritis) did not reflect the true clinical problem in a large proportion of our patients. This is particularly true when coding is performed by physicians outside the area of specialty of the diagnosis.

Vandenberghe LH. What Is Next for Retinal Gene Therapy?. Cold Spring Harb Perspect Med 2015;Abstract

The field of gene therapy for retinal blinding disorders is experiencing incredible momentum, justified by hopeful results in early stage clinical trials for inherited retinal degenerations. The premise of the use of the gene as a drug has come a long way, and may have found its niche in the treatment of retinal disease. Indeed, with only limited treatment options available for retinal indications, gene therapy has been proven feasible, safe, and effective and may lead to durable effects following a single injection. Here, we aim at putting into context the promise and potential, the technical, clinical, and economic boundaries limiting its application and development, and speculate on a future in which gene therapy is an integral component of ophthalmic clinical care.

Venturini G, Koskiniemi-Kuendig H, Harper S, Berson EL, Rivolta C. Two specific mutations are prevalent causes of recessive retinitis pigmentosa in North American patients of Jewish ancestry. Genet Med 2015;17(4):285-90.Abstract

PURPOSE: Retinitis pigmentosa is a Mendelian disease with a very elevated genetic heterogeneity. Most mutations are responsible for less than 1% of cases, making molecular diagnosis a multigene screening procedure. In this study, we assessed whether direct testing of specific alleles could be a valuable screening approach in cases characterized by prevalent founder mutations. METHODS: We screened 275 North American patients with recessive/isolate retinitis pigmentosa for two mutations: an Alu insertion in the MAK gene and the p.Lys42Glu missense in the DHDDS gene. All patients were unrelated; 35 reported Jewish ancestry and the remainder reported mixed ethnicity. RESULTS: We identified the MAK and DHDDS mutations homozygously in only 2.1% and 0.8%, respectively, of patients of mixed ethnicity, but in 25.7% and 8.6%, respectively, of cases reporting Jewish ancestry. Haplotype analyses revealed that inheritance of the MAK mutation was attributable to a founder effect. CONCLUSION: In contrast to most mutations associated with retinitis pigmentosa-which are, in general, extremely rare-the two alleles investigated here cause disease in approximately one-third of North American patients reporting Jewish ancestry. Therefore, their screening constitutes an alternative procedure to large-scale tests for patients belonging to this ethnic group, especially in time-sensitive situations.Genet Med 17 4, 285-290.

Wang Z, Cheng R, Lee K, Tyagi P, Ding L, Kompella UB, Chen J, Xu X, Ma J-X. Nanoparticle-mediated expression of a wnt pathway inhibitor ameliorates ocular neovascularization. Arterioscler Thromb Vasc Biol 2015;35(4):855-64.Abstract

OBJECTIVE: The deficiency of very low-density lipoprotein receptor resulted in Wnt signaling activation and neovascularization in the retina. The present study sought to determine whether the very low-density lipoprotein receptor extracellular domain (VLN) is responsible for the inhibition of Wnt signaling in ocular tissues. APPROACH AND RESULTS: A plasmid expressing the soluble VLN was encapsulated with poly(lactide-co-glycolide acid) to form VLN nanoparticles (VLN-NP). Nanoparticles containing a plasmid expressing the low-density lipoprotein receptor extracellular domain nanoparticle were used as negative control. MTT, modified Boyden chamber, and Matrigel (™) assays were used to evaluate the inhibitory effect of VLN-NP on Wnt3a-stimulated endothelial cell proliferation, migration, and tube formation. Vldlr(-/-) mice, oxygen-induced retinopathy, and alkali burn-induced corneal neovascularization models were used to evaluate the effect of VLN-NP on ocular neovascularization. Wnt reporter mice (BAT-gal), Western blotting, and luciferase assay were used to evaluate Wnt pathway activity. Our results showed that VLN-NP specifically inhibited Wnt3a-induced endothelial cell proliferation, migration, and tube formation. Intravitreal injection of VLN-NP inhibited abnormal neovascularization in Vldlr(-/-), oxygen-induced retinopathy, and alkali burn-induced corneal neovascularization models, compared with low-density lipoprotein receptor extracellular domain nanoparticle. VLN-NP significantly inhibited the phosphorylation of low-density lipoprotein receptor-related protein 6, the accumulation of β-catenin, and the expression of vascular endothelial growth factor in vivo and in vitro. CONCLUSIONS: Taken together, these results suggest that the soluble VLN is a negative regulator of the Wnt pathway and has antiangiogenic activities. Nanoparticle-mediated expression of VLN may thus represent a novel therapeutic approach to treat pathological ocular angiogenesis and potentially other vascular diseases affected by Wnt signaling.

Weis B, Schmidt J, Maamar H, Raj A, Lin H, Tóth C, Riedmann K, Raddatz G, Seitz H-K, Ho AD, Lyko F, Linhart HG. Inhibition of intestinal tumor formation by deletion of the DNA methyltransferase 3a. Oncogene 2015;34(14):1822-30.Abstract
Aberrant de novo methylation of DNA is considered an important mediator of tumorigenesis. To investigate the role of de novo DNA methyltransferase 3a (Dnmt3a) in intestinal tumor development, we analyzed the expression of Dnmt3a in murine colon crypts, murine colon adenomas and human colorectal cancer using RNA fluorescence in situ hybridization (FISH), quantitative PCR and immunostaining. Following conditional deletion of Dnmt3a in the colon of APC((Min/+)) mice, we analyzed tumor numbers, genotype of macroadenomas and laser dissected microadenomas, global and regional DNA methylation and gene expression. Our results showed increased Dnmt3a expression in colon adenomas of APC((Min/+)) mice and human colorectal cancer samples when compared with control tissue. Interestingly, in tumor tissue, RNA FISH analysis showed highest Dnmt3a expression in Lgr5-positive stem/progenitor cells. Deletion of Dnmt3a in APC((Min/+)) mice reduced colon tumor numbers by ~40%. Remaining adenomas and microadenomas almost exclusively contained the non-recombined Dnmt3a allele; no tumors composed of the inactivated Dnmt3a allele were detected. DNA methylation was reduced at the Oct4, Nanog, Tff2 and Cdkn1c promoters and expression of the tumor-suppressor genes Tff2 and Cdkn1c was increased. In conclusion, our results show that Dnmt3a is predominantly expressed in the stem/progenitor cell compartment of tumors and that deletion of Dnmt3a inhibits the earliest stages of intestinal tumor development.
Wu H, de Boer JF, Chen L, Chen TC. Correlation of localized glaucomatous visual field defects and spectral domain optical coherence tomography retinal nerve fiber layer thinning using a modified structure-function map for OCT. Eye (Lond) 2015;29(4):525-33.Abstract

PurposeTo study the correlation between glaucomatous visual field (VF) defects assessed by standard automated perimetry (SAP) and peripapillary retinal nerve fiber layer (RNFL) thinning measured by spectral domain optical coherence tomography (OCT) using a modified OCT-based peripapillary RNFL structure-function map.Patients and methodsPerimetric glaucoma patients and age-matched normal control subjects were recruited from a university hospital clinic. All eyes underwent testing with the Spectralis spectral domain OCT and SAP on the same day. An OCT-based correspondence map, which correlated VF areas with peripapillary RNFL sectors was created to evaluate the relationship between glaucomatous RNFL thinning and VF loss in six nerve fiber layer bundle areas. Correlations of RNFL thinning with corresponding VF defects were examined using Spearman rank-order correlations. To demonstrate the association between localized VF defects and RNFL thickness, the theoretical curves were made according to an established log-linear model. The measured RNFL thickness values and VF defects were presented in the same scatterplot for each sector.ResultsFifty-six glaucoma patients and 85 normal subjects were included in the study. Significant association between localized VF loss and RNFL thinning was found in corresponding areas. Data from the current study fit well with established log-linear models, which compare RNFL thickness values with VF defects.ConclusionAnalysis of RNFL thinning in eyes with localized glaucomatous VF defects showed good structure-function correlation in a new OCT-based structure-function correspondence map.