Retina

Chee YE, Eliott D. The Role of Vitrectomy in the Management of Fungal Endophthalmitis. Semin Ophthalmol 2017;32(1):29-35.Abstract

Fungal endophthalmitis is an important cause of vision loss worldwide with a large body of literature describing the treatment of the disease. The evidence supporting the use of pars plana vitrectomy in the management of fungal endophthalmitis is largely comprised of case reports and case series and demonstrates the important role of vitrectomy surgery. Vitrectomy can improve the likelihood of establishing the diagnosis, enhance the treatment of infection by removing fungal elements in the vitreous, aid in the removal of other inoculated intraocular structures, and is an important tool in the management of vision-threatening post-infectious sequelae like retinal detachment and epiretinal membrane.

Vodopivec I, Cestari DM, Rizzo JF. Management of Transient Monocular Vision Loss and Retinal Artery Occlusions. Semin Ophthalmol 2017;32(1):125-133.Abstract

Acute transient or permanent retinal occlusive disease requires prompt medical attention and can be an ophthalmological emergency. Central retinal artery occlusion leads to permanent and severe monocular visual loss in the majority of patients. Transient monocular vision loss leaves no permanent deficits, but requires the same level of clinical vigilance, as it portends possible future adverse events, including loss of vision and stroke. Acute treatment options remain limited, and secondary prevention of cerebral ischemic events is the mainstay of management. This article reviews the current evidence for managing patients with retinal ischemia.

Eliott D, Stryjewski TP, Andreoli MT, Andreoli CM. SMOKING IS A RISK FACTOR FOR PROLIFERATIVE VITREORETINOPATHY AFTER TRAUMATIC RETINAL DETACHMENT. Retina 2017;37(7):1229-1235.Abstract
PURPOSE: To determine the incidence of retinal redetachment due to proliferative vitreoretinopathy after open-globe trauma in smokers and nonsmokers. METHODS: A total of 892 patients comprising 893 open-globe injuries, in whom 255 eyes were diagnosed with a retinal detachment, and 138 underwent surgical repair were analyzed in a retrospective case-control study. Time to redetachment was examined using the Kaplan-Meier method and analysis of risk factors was analyzed using Cox proportional hazards modeling. RESULTS: Within one year after retinal detachment surgery, 47% (95% CI, 39-56%) of all 138 repaired retinas redetached because of proliferative vitreoretinopathy. Being a smoker was associated with a higher rate of detachment (adjusted hazard ratio 1.96, P = 0.01). As shown in previous studies, the presence of proliferative vitreoretinopathy at the time of surgery was also an independent risk factor for failure (adjusted hazard ratio 2.13, P = 0.005). Treatment with vitrectomy-buckle compared favorably to vitrectomy alone (adjusted hazard ratio 0.58, P = 0.04). Only 8% of eyes that redetached achieved a best-corrected visual acuity of 20/200 or better, in comparison to 44% of eyes that did not redetach (P < 0.001). CONCLUSION: Proliferative vitreoretinopathy is a common complication after the repair of retinal detachment associated with open-globe trauma, and being a smoker is a risk factor for redetachment. Further study is needed to understand the pathophysiologic mechanisms underlying this correlation.
Hansen RM, Moskowitz A, Akula JD, Fulton AB. The neural retina in retinopathy of prematurity. Prog Retin Eye Res 2017;56:32-57.Abstract

Retinopathy of prematurity (ROP) is a neurovascular disease that affects prematurely born infants and is known to have significant long term effects on vision. We conducted the studies described herein not only to learn more about vision but also about the pathogenesis of ROP. The coincidence of ROP onset and rapid developmental elongation of the rod photoreceptor outer segments motivated us to consider the role of the rods in this disease. We used noninvasive electroretinographic (ERG), psychophysical, and retinal imaging procedures to study the function and structure of the neurosensory retina. Rod photoreceptor and post-receptor responses are significantly altered years after the preterm days during which ROP is an active disease. The alterations include persistent rod dysfunction, and evidence of compensatory remodeling of the post-receptor retina is found in ERG responses to full-field stimuli and in psychophysical thresholds that probe small retinal regions. In the central retina, both Mild and Severe ROP delay maturation of parafoveal scotopic thresholds and are associated with attenuation of cone mediated multifocal ERG responses, significant thickening of post-receptor retinal laminae, and dysmorphic cone photoreceptors. These results have implications for vision and control of eye growth and refractive development and suggest future research directions. These results also lead to a proposal for noninvasive management using light that may add to the currently invasive therapeutic armamentarium against ROP.

Pasovic L, Eidet JR, Olstad OK, Chen DF, Lyberg T, Utheim TP. Impact of Storage Temperature on the Expression of Cell Survival Genes in Cultured ARPE-19 Cells. Curr Eye Res 2017;42(1):134-144.Abstract

PURPOSE: The development of a suitable storage method for retinal pigment epithelium (RPE) is necessary in the establishment of future RPE replacement therapy, and storage temperature has proven to be pivotal for cell survival. ARPE-19, a widely used model for RPE, has been shown to yield the greatest number of viable cells when stored at 16°C compared to other storage temperatures. In this study, we analyze the gene expression profile of cultured ARPE-19 cells after seven days of storage at different temperatures in an effort to predict the gene-level consequences of storage of RPE transplants. MATERIALS AND METHODS: ARPE-19 cells were cultured until confluence and then stored in minimum essential medium at 4°C, 16°C, and 37°C for seven days. The total RNA was isolated and the gene expression profile was determined using DNA microarrays. The Results were validated using qPCR. RESULTS: Principal component and hierarchical clustering analyses show that the gene expression profiles of cell cultures stored at different temperatures cluster into separate groups. Cultures stored at 4°C cluster closest to the control cultures that were not stored and display the least change in gene expression after storage (157 differentially expressed genes). Cultures stored at 16°C and 37°C display a much larger change in differential gene expression (1787 and 1357 differentially expressed genes, respectively). At 16°C, the expression of several genes with proposed tumor suppressor functions was markedly increased. Changes in regulation of several known signaling pathways and of oxidative stress markers were discovered at both 16°C and 37°C, and activation of the angiogenesis marker vascular endothelial growth factor (VEGF) was discovered at 37°C. There was no evidence of the activation of inflammatory processes in stored cell cultures. CONCLUSION: ARPE-19 cultures stored at 16°C show the greatest propensity to modulate their gene expression profile in a manner that supports cell survival during storage.

Wannamaker KW, Sharpe RA, Kylstra JA. SPONTANEOUS CLOSURE OF A MACULAR HOLE AFTER FOUR FAILED VITRECTOMIES IN THE SETTING OF NF-1. Retin Cases Brief Rep 2016;Abstract

PURPOSE: To present the case of a patient who developed spontaneous closure of an idiopathic macular hole after four failed attempts at surgical closure. METHODS: This is a retrospective case review of the medical record of a single patient. No statistical analysis was performed. The patient is a 71-year-old white woman with neurofibromatosis Type 1 who presented to the retina clinic of one of the authors. RESULTS: The patient underwent four vitrectomies with long acting gas by two surgeons over the course of 2 years. After each surgery, the hole either did not close or it closed and then reopened within 1 year. Five months after the last surgery (1 year after the hole last reopened), the patient presented with improved vision and spontaneous closure of the macular hole. The hole has remained closed since then. CONCLUSION: This case demonstrates that spontaneous closure of a macular hole, associated with excellent visual recovery, can occur after multiple surgical failures. We propose that enhanced scar formation due to neurofibromatosis Type 1 was responsible for both the numerous failures following initially successful surgery (centrifugal traction) and for the spontaneous closure (centripetal traction).

Sachdeva MM, Jakobiec FA, Stagner AM, Papakostas A, Eliott D. Clinical and Ultrastructural Studies of Epiretinal Pigmentary Deposits after Retinectomy with Silicone Oil. Ophthalmology 2016;123(12):2595-2602.Abstract

PURPOSE: Large relaxing retinectomies have become increasingly used in the repair of retinal detachment related to proliferative vitreoretinopathy (PVR). Retinectomies expose the retinal pigment epithelium (RPE) to the vitreous cavity; the direct effects of silicone oil on the RPE are only beginning to be understood. DESIGN: Retrospective case series. PARTICIPANTS: Twelve patients noted to develop pigmented epiretinal deposits at regularly scheduled follow-up visits after repair of complex retinal detachments using silicone oil tamponade and retinectomy. METHODS: Epiretinal pigment deposits were characterized clinically by wide-field color photography, fundus autofluorescence imaging, and spectral-domain optical coherence tomography (SD OCT). At the time of silicone oil removal, the pigmented membranes were preserved in fixative and analyzed by light microscopy/immunostaining or electron microscopy for histologic characterization. MAIN OUTCOME MEASURES: Not applicable. RESULTS: We describe the development of diffuse preretinal pigmentary deposits in 12 eyes after surgery for complicated PVR detachments using retinectomies with oil, with an average onset of 3.2 months postoperatively. These pigment clumps produced a striking leopard-spot pattern on fundus autofluorescence imaging. Histopathologic and ultrastructural analysis of these epiretinal proliferations peeled at the time of silicone oil removal revealed RPE cells with intracellular silicone oil droplets, singly dispersed membrane-bound melanin granules, glial tissue (1 case), and a fibrous stroma. CONCLUSIONS: Although in vitro studies have suggested that RPE cells can phagocytose emulsified oil droplets, this report represents the first in vivo documentation by electron microscopy of this phenomenon in patients. These findings underscore that direct contact with silicone oil may affect the behavior of the RPE, which may be clinically relevant in patients who have undergone large relaxing retinectomies with silicone oil tamponade for PVR-related retinal detachments.

Ramachandran P, Lee V, Wei Z, Song JY, Casal G, Cronin T, Willett K, Huckfeldt R, Morgan JIW, Aleman TS, Maguire AM, Bennett J. Evaluation of dose and safety of AAV7m8 and AAV8BP2 in the non-human primate retina. Hum Gene Ther 2016;Abstract

Within the next decade, we will see many gene therapy clinical trials for eye diseases progress, which may lead to treatments for thousands of visually impaired people around the world. To target retinal diseases that affect specific cell types, several recombinant adeno-associated virus (AAV) serotypes have been generated and used successfully in pre-clinical mouse studies. Because there are numerous anatomic, and physiologic differences between the eyes of mice and 'men' and because surgical delivery approaches and immunologic responses also differ between these species, we evaluated the transduction characteristics of two promising new serotypes AAV7m8 and AAV8BP2, in retinas of animals that are most similar to those of humans: non-human primates (NHPs). We report that while AAV7m8 efficiently targets a variety of cell types by subretinal injection in NHPs, transduction after intravitreal delivery was mostly restricted to the inner retina at lower doses that did not induce an immune response. AAV8BP2 targets the cone photoreceptors efficiently but bipolar cells inefficiently by subretinal injection. Additionally, we observed transduction of both serotypes in the anterior chamber of the eye and the optic pathway of the brain post intravitreal delivery. Finally, we assessed immunogenicity, keeping in mind that these AAV capsids may be used in future clinical trials. We found that AAV8BP2 had a better safety profile compared to AAV7m8 even at the highest doses administered. Our studies underscore the differences in AAV transduction between mice and primates highlighting the importance of careful evaluation of therapeutic vectors in NHPs prior to moving into clinical trials.

Wang Z, Liu C-H, Sun Y, Gong Y, Favazza TL, Morss PC, Saba NJ, Fredrick TW, He X, Akula JD, Chen J. Pharmacologic Activation of Wnt Signaling by Lithium Normalizes Retinal Vasculature in a Murine Model of Familial Exudative Vitreoretinopathy. Am J Pathol 2016;186(10):2588-600.Abstract

Familial exudative vitreoretinopathy (FEVR) is characterized by delayed retinal vascular development, which promotes hypoxia-induced pathologic vessels. In severe cases FEVR may lead to retinal detachment and visual impairment. Genetic studies linked FEVR with mutations in Wnt signaling ligand or receptors, including low-density lipoprotein receptor-related protein 5 (LRP5) gene. Here, we investigated ocular pathologies in a Lrp5 knockout (Lrp5(-/-)) mouse model of FEVR and explored whether treatment with a pharmacologic Wnt activator lithium could bypass the genetic defects, thereby protecting against eye pathologies. Lrp5(-/-) mice displayed significantly delayed retinal vascular development, absence of deep layer retinal vessels, leading to increased levels of vascular endothelial growth factor and subsequent pathologic glomeruloid vessels, as well as decreased inner retinal visual function. Lithium treatment in Lrp5(-/-) mice significantly restored the delayed development of retinal vasculature and the intralaminar capillary networks, suppressed formation of pathologic glomeruloid structures, and promoted hyaloid vessel regression. Moreover, lithium treatment partially rescued inner-retinal visual function and increased retinal thickness. These protective effects of lithium were largely mediated through restoration of canonical Wnt signaling in Lrp5(-/-) retina. Lithium treatment also substantially increased vascular tubular formation in LRP5-deficient endothelial cells. These findings suggest that pharmacologic activation of Wnt signaling may help treat ocular pathologies in FEVR and potentially other defective Wnt signaling-related diseases.

Davoudi S, Ahmadi T, Papavasilieou E, Leskov I, Sobrin L. Phage Immunoprecipitation Sequencing of Autoantigens in Autoimmune Retinopathy. Ocul Immunol Inflamm 2016;:1-8.Abstract

PURPOSE: To identify autoantigens in autoimmune retinopathy patients by phage immunoprecipitation sequencing (PhIP-Seq), a new technique for autoantigen discovery. METHODS: PhIP-Seq was used to sequence putative autoantibodies in plasma from 11 patients with autoimmune retinopathy and eight controls. We compared the autoantibodies' molecular weights with those of proteins detected by Western blot. RESULTS: Several autoantigens were found in cases and not detected in the controls. Autoantigens RTN3, PRPF6, TRPC6, and B3GNT8, four proteins expressed in the retina, were detected in plasma as autoantibodies from one patient each and no controls. Only one patient had an autoantibody, B3GNT8 (43.4 kDa), within a similar weight range as that detected by antiretinal antibody Western blot (42 kDa). Autoantibody POLR3A, which has a well-characterized role in scleroderma, was detected in two cases and no controls. CONCLUSION: PhIP-Seq detected autoantigens that are expressed in the retina as well as scleroderma-related autoantigens in autoimmune retinopathy patients.

Sehic A, Guo S, Cho K-S, Corraya RM, Chen DF, Utheim TP. Electrical Stimulation as a Means for Improving Vision. Am J Pathol 2016;186(11):2783-2797.Abstract

Evolving research has provided evidence that noninvasive electrical stimulation (ES) of the eye may be a promising therapy for either preserving or restoring vision in several retinal and optic nerve diseases. In this review, we focus on minimally invasive strategies for the delivery of ES and accordingly summarize the current literature on transcorneal, transorbital, and transpalpebral ES in both animal experiments and clinical studies. Various mechanisms are believed to underlie the effects of ES, including increased production of neurotrophic agents, improved chorioretinal blood circulation, and inhibition of proinflammatory cytokines. Different animal models have demonstrated favorable effects of ES on both the retina and the optic nerve. Promising effects of ES have also been demonstrated in clinical studies; however, all current studies have a lack of randomization and/or a control group (sham). There is thus a pressing need for a deeper understanding of the underlying mechanisms that govern clinical success and optimization of stimulation parameters in animal studies. In addition, such research should be followed by large, prospective, clinical studies to explore the full potential of ES. Through this review, we aim to provide insight to guide future research on ES as a potential therapy for improving vision.

Arno G, Hull S, Carss K, Dev-Borman A, Chakarova C, Bujakowska K, van den Born I, Robson AG, Holder GE, Michaelides M, Cremers FPM, Pierce E, Raymond LF, Moore AT, Webster AR. Reevaluation of the Retinal Dystrophy Due to Recessive Alleles of RGR With the Discovery of a Cis-Acting Mutation in CDHR1. Invest Ophthalmol Vis Sci 2016;57(11):4806-13.Abstract

PURPOSE: Mutation of RGR, encoding retinal G-protein coupled receptor was originally reported in association with retinal dystrophy in 1999. A single convincing recessive variant segregated perfectly in one family of five affected and two unaffected siblings. At least one further individual, homozygous for the same variant has since been reported. The aim of this report was to reevaluate the findings in consideration of data from a whole genome sequencing (WGS) study of a large cohort of retinal dystrophy families. METHODS: Whole genome sequencing was performed on 599 unrelated probands with inherited retinal disease. Detailed phenotyping was performed, including clinical evaluation, electroretinography, fundus photography, fundus autofluorescence imaging (FAF) and spectral-domain optical coherence tomography (OCT). RESULTS: Overall we confirmed that affected individuals from six unrelated families were homozygous for both the reported RGR p.Ser66Arg variant and a nearby frameshifting deletion in CDHR1 (p.Ile841Serfs119*). All had generalized rod and cone dysfunction with severe macular involvement. An additional proband was heterozygous for the same CDHR1/RGR haplotype but also carried a second null CDHR1 mutation on a different haplotype. A comparison of the clinical presentation of the probands reported here with other CDHR1-related retinopathy patients shows the phenotypes to be similar in presentation, severity, and rod/cone involvement. CONCLUSIONS: These data suggest that the recessive retinal disorder previously reported to be due to homozygous mutation in RGR is, at least in part, due to variants in CDHR1 and that the true consequences of RGR knock-out on human retinal structure and function are yet to be determined.

Liu C-H, Wang Z, Sun Y, SanGiovanni JP, Chen J. Retinal expression of small non-coding RNAs in a murine model of proliferative retinopathy. Sci Rep 2016;6:33947.Abstract

Ocular neovascularization is a leading cause of blindness in proliferative retinopathy. Small non-coding RNAs (sncRNAs) play critical roles in both vascular and neuronal development of the retina through post-transcriptional regulation of target gene expression. To identify the function and therapeutic potential of sncRNAs in retinopathy, we assessed the expression profile of retinal sncRNAs in a mouse model of oxygen-induced retinopathy (OIR) with pathologic proliferation of neovessels. Approximately 2% of all analyzed sncRNAs were significantly altered in OIR retinas compared with normoxic controls. Twenty three microRNAs with substantial up- or down-regulation were identified, including miR-351, -762, -210, 145, -155, -129-5p, -150, -203, and -375, which were further analyzed for their potential target genes in angiogenic, hypoxic, and immune response-related pathways. In addition, nineteen small nucleolar RNAs also revealed differential expression in OIR retinas compared with control retinas. A decrease of overall microRNA expression in OIR retinas was consistent with reduced microRNA processing enzyme Dicer, and increased expression of Alu element in OIR. Together, our findings elucidated a group of differentially expressed sncRNAs in a murine model of proliferative retinopathy. These sncRNAs may exert critical post-transcriptional regulatory roles in regulating pathological neovascularization in eye diseases.

Reddy DN, Yonekawa Y, Thomas BJ, Nudleman ED, Williams GA. Long-term surgical outcomes of retinal detachment in patients with Stickler syndrome. Clin Ophthalmol 2016;10:1531-4.Abstract

PURPOSE: The aim of the study was to present the long-term anatomical and visual outcomes of retinal detachment repair in patients with Stickler syndrome. PATIENTS AND METHODS: This study is a retrospective, interventional, consecutive case series of patients with Stickler syndrome undergoing retinal reattachment surgery from 2009 to 2014 at the Associated Retinal Consultants, William Beaumont Hospital. RESULTS: Sixteen eyes from 13 patients were identified. Patients underwent a mean of 3.1 surgical interventions (range: 1-13) with a mean postoperative follow-up of 94 months (range: 5-313 months). Twelve eyes (75%) developed proliferative vitreoretinopathy. Retinal reattachment was achieved in 100% of eyes, with ten eyes (63%) requiring silicone oil tamponade at final follow-up. Mean preoperative visual acuity (VA) was 20/914, which improved to 20/796 at final follow-up (P=0.81). There was a significant correlation between presenting and final VA (P<0.001), and patients with poorer presenting VA were more likely to require silicone oil tamponade at final follow-up (P=0.04). CONCLUSION: Repair of retinal detachment in patients with Stickler syndrome often requires multiple surgeries, and visual outcomes are variable. Presenting VA is significantly predictive of long-term VA outcomes.

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