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Escuder AG, Kazlas MA, Heidary G, Hunter DG, Zurakowski D, Dagi LR. Incidence of symptomatic vertical and torsional diplopia after superior rectus transposition for esotropic Duane syndrome and abducens nerve palsy. J AAPOS 2020;Abstract
PURPOSE: To report the incidence of symptomatic vertical and torsional diplopia after superior rectus transposition (SRT) for esotropic Duane syndrome and abducens nerve palsy. METHODS: The medical records of patients with esotropic Duane syndrome or abducens nerve palsy seen at Boston Children's Hospital (2006-2018) and treated with unilateral SRT with or without augmentation was performed. The primary outcome was incidence of postoperative vertical or torsional diplopia in primary position. The secondary outcome was induced vertical deviation in affected side gaze. RESULTS: A total of 69 patients met inclusion criteria: 32 with abducens nerve palsy and 37 with esotropic Duane syndrome. Vertical alignment changed in both hyper- and hypotropic directions. Median pre- and postoperative vertical deviation in primary gaze was 1.1 (10th-90th percentile, 0-6 hypertropia) and 0.4 (10th-90th percentile, 6 hypotropia to 8 hypertropia), respectively. Postoperative vertical diplopia occurred in 7%, including 4 of 49 treated with loop myopexy (8%), 1 of 13 without augmentation (8%), and 0 of 7 treated with sclera-fixated augmentation. All but one was successfully treated with prism or secondary surgery. Intorsional change predominated, but no patient had torsional diplopia post adjustment. Vertical misalignment in affected side gaze increased from 19% to 45% after SRT (P = 0.01). CONCLUSIONS: In this largest-to-date review of patients treated with SRT, with or without MR recession, no patient developed persistent torsional diplopia, while 7% developed symptomatic vertical diplopia in primary position, similar to the reported incidence after balanced vertical rectus transposition. Vertical misalignment in affected side gaze increased, however fusion is already limited by unresolved esotropia in this field.
Tayebi B, Sharif F, Han J-H. Smart filtering of phase residues in noisy wrapped holograms. Sci Rep 2020;10(1):16965.Abstract
Phase unwrapping is one of the major challenges in multiple branches of science that extract three-dimensional information of objects from wrapped signals. In several applications, it is important to extract the unwrapped information with minimal signal resolution degradation. However, most of the denoising techniques for unwrapping are designed to operate on the entire phase map to remove a limited number of phase residues, and therefore they significantly degrade critical information contained in the image. In this paper, we present a novel, smart, and automatic filtering technique for locally minimizing the number of phase residues in noisy wrapped holograms, based on the phasor average filtering (PAF) of patches around each residue point. Both patch sizes and PAF filters are increased in an iterative algorithm to minimize the number of residues and locally restrict the artifacts caused by filtering to the pixels around the residue pixels. Then, the improved wrapped phase can be unwrapped using a simple phase unwrapping technique. The feasibility of our method is confirmed by filtering, unwrapping, and enhancing the quality of a noisy hologram of neurons; the intensity distribution of the spatial frequencies demonstrates a 40-fold improvement, with respect to previous techniques, in preserving the higher frequencies.
Li Y, He X, Kawaguchi R, Zhang Y, Wang Q, Monavarfeshani A, Yang Z, Chen B, Shi Z, Meng H, Zhou S, Zhu J, Jacobi A, Swarup V, Popovich PG, Geschwind DH, He Z. Microglia-organized scar-free spinal cord repair in neonatal mice. Nature 2020;587(7835):613-618.Abstract
Spinal cord injury in mammals is thought to trigger scar formation with little regeneration of axons. Here we show that a crush injury to the spinal cord in neonatal mice leads to scar-free healing that permits the growth of long projecting axons through the lesion. Depletion of microglia in neonatal mice disrupts this healing process and stalls the regrowth of axons, suggesting that microglia are critical for orchestrating the injury response. Using single-cell RNA sequencing and functional analyses, we find that neonatal microglia are transiently activated and have at least two key roles in scar-free healing. First, they transiently secrete fibronectin and its binding proteins to form bridges of extracellular matrix that ligate the severed ends of the spinal cord. Second, neonatal-but not adult-microglia express several extracellular and intracellular peptidase inhibitors, as well as other molecules that are involved in resolving inflammation. We transplanted either neonatal microglia or adult microglia treated with peptidase inhibitors into spinal cord lesions of adult mice, and found that both types of microglia significantly improved healing and axon regrowth. Together, our results reveal the cellular and molecular basis of the nearly complete recovery of neonatal mice after spinal cord injury, and suggest strategies that could be used to facilitate scar-free healing in the adult mammalian nervous system.
Narayanan D, Rodriguez J, Wallstrom G, Welch D, Chapin M, Arrigg P, Abelson M. An exploratory study to evaluate visual function endpoints in non-advanced age-related macular degeneration. BMC Ophthalmol 2020;20(1):424.Abstract
BACKGROUND: To prevent irreversible vision loss in age-related macular degeneration (AMD), it is critical to detect retinal dysfunction before permanent structural loss occurs. In the current study we evaluated a series of visual function tests to identify potential endpoints to detect visual dysfunction in non-advanced AMD. METHODS: A series of visual function tests were performed on 23 non-advanced AMD subjects (AREDS grade 1-4 on simplified scale) and 34 age-matched normals (AREDS grade 0). Tests included some commonly used endpoints such as ETDRS visual acuity (VA), low luminance (LL) 2.0ND ETDRS VA, MNREAD as well as newly developed tests such as the Ora-VCF™ test, Ora-tablet reading test, color sensitivity etc. Differences between the two groups were compared for each test. Test-retest repeatability and reproducibility was assessed on a subset of subjects and percent agreement was calculated. RESULTS: There was no difference in standard ETDRS VA between non-advanced AMD (0.06 ± 0.02 logMAR) and normal groups (0.04 ± 0.02 logMAR) (p = 0.57). LL 2.0 ETDRS VA and MNREAD showed no difference between the groups (p > 0.05). Ora-VCF™ test was significantly worse in the non-advanced AMD group compared to normals (0.67 ± 0.07 in AMD; 0.45 ± 0.04 in normals, p = 0.005). Non-advanced AMD subjects also had significantly worse reading performance using the Ora-tablet with LL 2.0ND (114.55 ± 11.22 wpm in AMD; 145.17 ± 9.55 wpm in normals p = 0.049). No significant difference between the groups was noted using other tests. Repeatability was 82% for Ora-VCF™ test and 92% for Ora-tablet LL 2.0ND reading. Reproducibility was 89% for both Ora-VCF™ test and Ora-tablet LL 2.0ND reading. CONCLUSION: While there was no significant difference between non-advanced AMD and normal groups using some current common endpoints such as ETDRS VA, LL 2.0 ETDRS VA or MNREAD, Ora-VCF™ test and Ora-tablet LL 2.0ND reading tests were able to identify significant visual dysfunction in non-advanced AMD subjects. These tests show promise as endpoints for AMD studies.
Shire DB, Gingerich MD, Wong PI, Skvarla M, Cogan SF, Chen J, Wang W, Rizzo JF. Micro-Fabrication of Components for a High-Density Sub-Retinal Visual Prosthesis. Micromachines (Basel) 2020;11(10)Abstract
We present a retrospective of unique micro-fabrication problems and solutions that were encountered through over 10 years of retinal prosthesis product development, first for the Boston Retinal Implant Project initiated at the Massachusetts Institute of Technology and at Harvard Medical School's teaching hospital, the Massachusetts Eye and Ear-and later at the startup company Bionic Eye Technologies, by some of the same personnel. These efforts culminated in the fabrication and assembly of 256+ channel visual prosthesis devices having flexible multi-electrode arrays that were successfully implanted sub-retinally in mini-pig animal models as part of our pre-clinical testing program. We report on the processing of the flexible multi-layered, planar and penetrating high-density electrode arrays, surgical tools for sub-retinal implantation, and other parts such as coil supports that facilitated the implantation of the peri-ocular device components. We begin with an overview of the implantable portion of our visual prosthesis system design, and describe in detail the micro-fabrication methods for creating the parts of our system that were assembled outside of our hermetically-sealed electronics package. We also note the unique surgical challenges that sub-retinal implantation of our micro-fabricated components presented, and how some of those issues were addressed through design, materials selection, and fabrication approaches.
Jacob A, Brun L, Gil PJ, Ménard L, Bouzelha M, Broucque F, Roblin A, Vandenberghe LH, Adjali O, Robin C, François A, Blouin V, Penaud-Budloo M, Ayuso E. Homologous Recombination Offers Advantages Over Transposition-Based Systems to Generate Recombinant Baculovirus for Adeno-Associated Viral Vector Production. Biotechnol J 2020;:e2000014.Abstract
Viral vectors have a great potential for gene delivery, but manufacturing at a pharmaceutical scale is a big challenge for the industry. The baculovirus-insect cell system is one of the most scalable platforms to produce clinical-grade recombinant Adeno-Associated Virus (rAAV) vectors. The standard procedure to generate recombinant baculovirus is based on Tn7 transposition which is time-consuming and still suffers technical constraints. Moreover, werecently showed that baculoviral sequences adjacent to the AAV ITRs are preferentially encapsidated into the rAAV vector particles. This observation raised concerns about safety for clinical applications due to the presence of bacterial and antibiotic resistance coding sequences with a Tn7-mediated system for the construction of baculoviruses reagents. Here, weinvestigated a faster and safer method based on homologous recombination (HR). First, weconfirmed the functionality of the inserted cassette and the absence of undesirable genes into HR-derived baculoviral genomes. Strikingly, wefound that the exogenous cassette showed increased stability over passages when using the HR system. Finally, wetested these materials to produce rAAV vectors. The baculoviruses originated from both systems lead to high rAAV vector genome yields, with the advantage of the HR system being exempted from undesirable bacterial genes which provides an additional level of safety for the manufacturing of rAAV vectors. Overall, this study highlights the importance of the upstream process and starting biologic materials to generate safer rAAV biotherapeutic products. This article is protected by copyright. All rights reserved.
Zhang Y, Wang K, Pan J, Yang S, Yao H, Li M, Li H, Lei H, Jin H, Wang F. Exosomes mediate an epithelial-mesenchymal transition cascade in retinal pigment epithelial cells: Implications for proliferative vitreoretinopathy. J Cell Mol Med 2020;Abstract
Exosomes have recently emerged as a pivotal mediator of many physiological and pathological processes. However, the role of exosomes in proliferative vitreoretinopathy (PVR) has not been reported. In this study, we aimed to investigate the role of exosomes in PVR. Transforming growth factor beta 2 (TGFß-2) was used to induce epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells, as an in vitro model of PVR. Exosomes from normal and EMTed RPE cells were extracted and identified. We incubated extracted exosomes with recipient RPE cells, and co-cultured EMTed RPE cells and recipient RPE cells in the presence of the exosome inhibitor GW4869. Both experiments suggested that there are further EMT-promoting effects of exosomes from EMTed RPE cells. MicroRNA sequencing was also performed to identify the miRNA profiles in exosomes from both groups. We identified 34 differentially expressed exosomal miRNAs (P <. 05). Importantly, miR-543 was found in exosomes from EMTed RPE cells, and miR-543-enriched exosomes significantly induced the EMT of recipient RPE cells. Our study demonstrates that exosomal miRNA is differentially expressed in RPE cells during EMT and that these exosomal miRNAs may play pivotal roles in EMT induction. Our results highlight the importance of exosomes as cellular communicators within the microenvironment of PVR.
Valdes L, Bispo P, Sobrin L. Application of Metagenomic Sequencing in the Diagnosis of Infectious Uveitis. Semin Ophthalmol 2020;:1-4.Abstract
: to summarize the origin and very recent history of the use of metagenomic sequencing for the diagnosis of infectious uveitis, convey the technique as described by one of the primary institutions experimenting with the technology, and present recent successful applications of the technology as well as potential advantages and pitfalls compared to other current diagnostic tools.: review of peer-reviewed literature concerning metagenomic sequencing for the diagnosis of infectious uveitis.: compared to existing diagnostic methods, metagenomic deep sequencing is a sensitive, unbiased, and comprehensive technique with great potential for diagnosing the causative pathogens of cases of infectious uveitis. However, many issues remain to be addressed in the process of developing this technology, including but not limited to the potentially overwhelming amount of information generated, definition of diagnostic thresholds, demonstration of validity, contamination, and cost.
Tomita Y, Lee D, Tsubota K, Kurihara T. PPARα Agonist Oral Therapy in Diabetic Retinopathy. Biomedicines 2020;8(10)Abstract
Diabetic retinopathy (DR) is an eye condition that develops after chronically poorly-managed diabetes, and is presently the main cause for blindness on a global scale. Current treatments for DR such as laser photocoagulation, topical injection of corticosteroids, intravitreal injection of anti-vascular endothelial growth factor (VEGF) agents and vitreoretinal surgery are only applicable at the late stages of DR and there are possibilities of significant adverse effects. Moreover, the forms of treatment available for DR are highly invasive to the eyes. Safer and more effective pharmacological treatments are required for DR treatment, in particular at an early stage. In this review, we cover recently investigated promising oral pharmacotherapies, the methods of which are safer, easier to use, patient-friendly and pain-free, in clinical studies. We especially focus on peroxisome proliferator-activator receptor alpha (PPARα) agonists in which experimental evidence suggests PPARα activation may be closely related to the attenuation of vascular damages, including lipid-induced toxicity, inflammation, an excess of free radical generation, endothelial dysfunction and angiogenesis. Furthermore, oral administration of selective peroxisome proliferator-activated receptor alpha modulator (SPPARMα) agonists may induce hepatic fibroblast growth factor 21 expression, indirectly resulting in retinal protection in animal studies. Our review will enable more comprehensive approaches for understanding protective roles of PPARα for the prevention of DR development.
Brazile BL, Yang B, Waxman S, Lam P, Voorhees AP, Hua Y, Loewen RT, Loewen NA, Rizzo JF, Jakobs T, Sigal IA. Lamina Cribrosa Capillaries Straighten as Intraocular Pressure Increases. Invest Ophthalmol Vis Sci 2020;61(12):2.Abstract
Purpose: The purpose of this study was to visualize the lamina cribrosa (LC) capillaries and collagenous beams, measure capillary tortuosity (path length over straight end-to-end length), and determine if capillary tortuosity changes when intraocular pressure (IOP) increases. Methods: Within 8 hours of sacrifice, 3 pig heads were cannulated via the external ophthalmic artery, perfused with PBS to remove blood, and then perfused with a fluorescent dye to label the capillaries. The posterior pole of each eye was mounted in a custom-made inflation chamber for control of IOP with simultaneous imaging. Capillaries and collagen beams were visualized with structured light illumination enhanced imaging at IOPs from 5 to 50 mm Hg at each 5 mm Hg increment. Capillary tortuosity was measured from the images and paired two-sample t-tests were used to assess for significant changes in relation to changes in IOP. Results: Capillaries were highly tortuous at 15 mm Hg (up to 1.45). In all but one eye, tortuosity decreased significantly as IOP increased from 15 to 25 mm Hg (P < 0.01), and tortuosity decreased significantly in every eye as IOP increased from 15 to 40 mm Hg (P < 0.01). In only 16% of capillaries, tortuosity increased with elevated IOP. Capillaries had a surprisingly different topology from the collagen beams. Conclusions: Although high capillary tortuosity is sometimes regarded as potentially problematic because it can reduce blood flow, LC capillary tortuosity may provide slack that mitigates against reduced flow and structural damage caused by excessive stretch under elevated IOP. We speculate that low capillary tortuosity could be a risk factor for damage under high IOP.
Cakir B, Hellström W, Tomita Y, Fu Z, Liegl R, Winberg A, Hansen-Pupp I, Ley D, Hellström A, Löfqvist C, Smith LEH. IGF1, serum glucose, and retinopathy of prematurity in extremely preterm infants. JCI Insight 2020;5(19)Abstract
BACKGROUNDHyperglycemia, insulin insensitivity, and low IGF1 levels in extremely preterm infants are associated with an increased risk of retinopathy of prematurity (ROP), but the interactions are incompletely understood.METHODSIn 117 extremely preterm infants, serum glucose levels and parenteral glucose intake were recoded daily in the first postnatal week. Serum IGF1 levels were measured weekly. Mice with oxygen-induced retinopathy alone versus oxygen-induced retinopathy plus streptozotocin-induced hyperglycemia/hypoinsulinemia were assessed for glucose, insulin, IGF1, IGFBP1, and IGFBP3 in blood and liver. Recombinant human IGF1 was injected to assess the effect on glucose and retinopathy.RESULTSThe highest mean plasma glucose tertile of infants positively correlated with parenteral glucose intake [r(39) = 0.67, P < 0.0001]. IGF1 plasma levels were lower in the high tertile compared with those in low and intermediate tertiles at day 28 (P = 0.038 and P = 0.03). In high versus lower glucose tertiles, ROP was more prevalent (34 of 39 versus 19 of 39) and more severe (ROP stage 3 or higher; 71% versus 32%). In oxygen-induced retinopathy, hyperglycemia/hypoinsulinemia decreased liver IGF1 expression (P < 0.0001); rh-IGF1 treatment improved normal vascular regrowth (P = 0.027) and reduced neovascularization (P < 0.0001).CONCLUSIONIn extremely preterm infants, high early postnatal plasma glucose levels and signs of insulin insensitivity were associated with lower IGF1 levels and increased ROP severity. In a hyperglycemia retinopathy mouse model, decreased insulin signaling suppressed liver IGF1 production, lowered serum IGF1 levels, and increased neovascularization. IGF1 supplementation improved retinal revascularization and decreased pathological neovascularization. The data support IGF1 as a potential treatment for prevention of ROP.TRIAL REGISTRATIONClinicalTrials.gov NCT02760472 (Donna Mega).FUNDINGThis study has been supported by the Swedish Medical Research Council (14940, 4732, 20144-01-3, and 21144-01-3), a Swedish government grant (ALFGB2770), Lund medical faculty grants (ALFL, 11615 and 11601), the Skåne Council Foundation for Research and Development, the Linnéa and Josef Carlsson Foundation, the Knut and Alice Wallenberg Foundation, the NIH/National Eye Institute (EY022275, EY017017, EY017017-13S1, and P01 HD18655), European Commission FP7 project 305485 PREVENT-ROP, Deutsche Forschungsgemeinschaft (CA-1940/1-1), and Stiftelsen De Blindas Vänner.
Maleki A, Gomez S, Asgari S, Bosenberg Z, Manhapra A, Walsh M, Weng A, Tseng C, He C, Anesi SD, Foster SC. Diagnostic and Prognostic Roles of Serum Interleukin-6 Levels in Patients with Uveitis. Ocul Immunol Inflamm 2020;:1-6.Abstract
PURPOSE: To examine the diagnostic and prognostic roles of serum interleukin-6 levels in patients with uveitis. METHODS: This was a retrospective observational case series. Demographic and clinical characteristics were compared between Group One (sixty patients) with normal serum IL-6 levels and Group Two (twenty patients) with high serum interleukin-6 levels. RESULTS: Mean IL-6 level was 1.77 ± 0.97 pg/ml and 10.2 ± 9.7 pg/ml in Group One and Group Two respectively. Age, presence of systemic disease, and mean number of flare-ups were statistically significant ( = .015, = .000, = .03, respectively). Multivariate analysis was performed on variables that were statistically significant in univariate analysis and showed that three variables had significant correlation with IL-6 levels in both groups: systemic disease (OR = 10.83, < .001), Age (OR = 0.95, = .03) and number of flare-ups (OR = 2.9, = .02). CONCLUSION: Serum IL-6 levels can provide diagnostic and prognostic information in regard to the course of disease and its treatment.

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