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Winter A, Chwalisz B. MRI Characteristics of NMO, MOG and MS Related Optic Neuritis. Semin Ophthalmol 2021;:1-10.Abstract
Acute isolated optic neuritis can be the initial presentation of demyelinating inflammatory central nervous system disease related to multiple sclerosis (MS), neuromyelitis optica (NMO) or myelin oligodendrocyte glycoprotein antibody disease (MOG-AD). In addition to the well-characterized brain and spinal cord imaging features, important and characteristic differences in the radiologic appearance of the optic nerves in these disorders are being described, and magnetic resonance imaging (MRI) of the optic nerves is becoming an essential tool in the differential diagnosis of optic neuritis. Whereas typical demyelinating optic neuritis is a relatively mild and self-limited disease, atypical optic neuritis in NMO and MOG-AD is potentially much more vision-threatening and merits a different treatment approach. Thus, differentiation based on MRI features may be particularly important during the first attack of optic neuritis, when antibody status is not yet known. This review discusses the optic nerve imaging in the major demyelinating disorders with an emphasis on clinically relevant differences that can help clinicians assess and manage these important neuro-ophthalmic disorders. It also reviews the utility of optic nerve MRI as a prognostic indicator in acute optic neuritis.
Ebrahimiadib N, Maleki A, Fadakar K, Manhapra A, Ghassemi F, Foster SC. Vascular abnormalities in uveitis. Surv Ophthalmol 2021;66(4):653-667.Abstract
Inflammation can involve several ocular structures, including the sclera, retina, and uvea, and cause vascular changes in these tissues. Although retinal vasculitis is the most common finding associated with uveitis involving the posterior segment, other vascular abnormalities may be seen in the retina. These include capillary nonperfusion and ischemia, vascular occlusions, preretinal neovascularization, microaneurysms and macroaneurysms, and telangiectasia. Moreover, vasoproliferative tumors and subsequent coat-like response can develop secondary to uveitis. Fluorescein angiography is ideal for the investigation of retinal vascular leakage and neovascularization, while optical coherence tomography angiography can provide depth resolved images from the superficial and deep capillary plexus and can demonstrate vascular remodeling. Choroidal vascular abnormalities primarily develop in the choriocapillaris or in the choroidal stroma and can appear as flow void in optical coherence tomography angiography and filling defect and vascular leakage in indocyanine green angiography. Extensive choriocapillaris nonperfusion in the presence of choroidal inflammation can increase the risk of choroidal neovascular membrane development. Iris vascular changes may manifest as dilation of vessels in stroma due to inflammation or rubeosis that is usually from ischemia in retinal periphery secondary to chronic inflammation. More severe forms of scleral inflammation, such as necrotizing scleritis, are associated with vascular occlusion in the deep episcleral plexus, which can lead to necrosis of sclera layer and uveal exposure.
Gu P, Fan T, Wong SSC, Pan Z, Tai WL, Chung SK, Cheung CW. Central Endothelin-1 Confers Analgesia by Triggering Spinal Neuronal Histone Deacetylase 5 (HDAC5) Nuclear Exclusion in Peripheral Neuropathic Pain in Mice. J Pain 2021;22(4):454-471.Abstract
The rationale of spinal administration of endothelin-1(ET-1) mediated anti-nociceptive effect has not been elucidated. ET-1 is reported to promote nuclear effluxion of histone deacetylase 5 (HDAC5) in myocytes, and spinal HDAC5 is implicated in modulation of pain processing. In this study, we aimed to investigate whether central ET-1 plays an anti-nociceptive role by facilitating spinal HDAC5 nuclear shuttling under neuropathic pain. Here, we demonstrate that upregulating spinal ET-1 attenuated the nociception induced by partial sciatic nerve ligation surgery and this analgesic effect mediated by ET-1 was attenuated by intrathecal injection of endothelin A receptor selective inhibitor (BQ123) or by blocking the exportation of nuclear HDAC5 by adeno-associated viruses targeting neuronal HDAC5 (AVV-HDAC5 S259/498A Mutant). Notably, ET-1 administration increased spinal glutamate acid decarboxylases (GAD65/67) expression via initiating HDAC5 nuclear exportation and increased the acetylation of histone 3 at lysine 9 (Acetyl-H3K9) in the promotor regions of spinal Gad1 and Gad2 genes. This was reversed by blocking endothelin A receptor function or by inhibiting the spinal neuronal nuclear exportation of HDAC5. Therefore, inducing spinal GABAergic neuronal HDAC5 nuclear exportation may be a novel therapeutic approach for managing neuropathic pain. PERSPECTIVE: Neuropathic pain is intractable in a clinical setting, and epigenetic regulation is considered to contribute to this processing. Characterizing the anti-nociceptive effect of ET-1 and investigating the associated epigenetic mechanisms in animal models may lead to the development of new therapeutic strategies and targets for treating neuropathic pain.
Yan Y, Ludwig CA, Liao YJ. Multimodal Imaging Features of Optic Disc Drusen. Am J Ophthalmol 2021;Abstract
PURPOSE: Identify key en face multimodal imaging features of optic disc drusen (ODD). DESIGN: Retrospective cross-sectional study. METHODS: . SETTING: Single academic center. PATIENT OR STUDY POPULATION: 786 patients (age 10-82 years) with diagnostic codes for ODD or the term "optic disc drusen" in clinical notes extracted using natural language processing. INTERVENTION OR OBSERVATION PROCEDURES: Color fundus image, green-light and blue-light fundus autofluorescence (FAF), near-infrared reflectance (NIR), and enhanced-depth imaging optical coherence tomography (EDI-OCT). MAIN OUTCOME MEASURES: Ophthalmic imaging characteristics and sensitivity of en face imaging compared with EDI-OCT. RESULTS: 38 (61 eyes) of 786 patients had high-quality EDI-OCT and en face multimodal imaging. Green-light FAF had the highest sensitivity (96.8%) and showed homogeneously hyperautofluorescence while blue-light FAF differentiated superficial and deep ODD by the heterogeneous brightness of FAF. Blue-light FAF (93.5%) and NIR (91.8%) were also sensitive and provided important features including the location, size, and depth of ODD and morphology of the optic disc and ODD-associated features such as horizontal hyperreflective lines and peripapillary hyperreflective ovoid mass-like structures (PHOMS), respectively. Color fundus imaging had the lowest sensitivity (82%). There was good inter-rater reliability for all en face imaging modalities (P < .0001 for all). CONCLUSIONS: Green-light FAF had the highest sensitivity in diagnosis of ODD, while blue-light FAF and NIR provided more information regarding the severity, location, depth, and size of ODD. In eyes that are negative on green-light FAF, EDI-OCT can be performed and provides the highest-resolution characterization of the entire optic disc to rule out ODD.
Davies E. Case Series: Novel Utilization of Rho-Kinase Inhibitor for the Treatment of Corneal Edema. Cornea 2021;40(1):116-120.Abstract
PURPOSE: To describe 3 cases of corneal clearance after the use of topical rho-kinase inhibitor, netarsudil, in the setting of endothelial cell dysfunction in comparison to one case without corneal clearance after the use of netarsudil. METHODS: Four patients presenting to a busy academic clinical corneal practice with visual complaints from corneal edema secondary to endothelial cell dysfunction were treated with topical netarsudil one drop daily in the affected eye. RESULTS: Corneal clearance was observed in 1) a case of peripheral corneal edema in the setting of iridocorneal endothelial syndrome after 4 weeks on netarsudil, 2) a case of corneal edema in the setting of early penetrating keratoplasty graft failure after 2-week use of netarsudil, and 3) a case of corneal edema in the setting of chronic penetrating keratoplasty graft failure after 4-week use of netarsudil. Corneal clearance was not observed in a case of corneal edema in the setting of pseudophakic bullous keratopathy from previous complicated intraocular lens exchange surgery with placement of an anterior chamber intraocular lens after the use of netarsudil for 12 weeks. CONCLUSIONS: Addition of topical rho-kinase inhibitor in the form of netarsudil can result in corneal clearance in a variety of certain cases of endothelial cell dysfunction, not previously documented in the literature.
Di Zazzo A, Gaudenzi D, Yin J, Coassin M, Fernandes M, Dana R, Bonini S. Corneal angiogenic privilege and its failure. Exp Eye Res 2021;204:108457.Abstract
The cornea actively maintains its own avascular status to preserve its ultimate optical function. This corneal avascular state is also defined as "corneal angiogenic privilege", which results from a critical and sensitive balance between anti-angiogenic and pro-angiogenic mechanisms. In our review, we aim to explore the complex equilibrium among multiple mediators which prevents neovascularization in the resting cornea, as well as to unveil the evolutive process which leads to corneal angiogenesis in response to different injuries.
Woodward AM, Senchyna M, Argüeso P. Short-Term Reproducibility of MUC5AC Measurement in Human Tear Fluid. Diagnostics (Basel) 2021;11(1)Abstract
The assessment of tear fluid components is a common and valuable approach to understanding ocular surface disease and testing the efficacy of novel therapeutic strategies. However, the interpretation and utility of the findings can be limited by changes in the composition of the tear film, particularly in studies requiring repetitive patient sampling. Here, tear samples were collected twice within a one-hour interval to evaluate the short-term reproducibility of an immunoassay aimed to measure the amount of MUC5AC mucin. We found no statistical difference in total protein or MUC5AC content between the two consecutive collections of tear fluid, although the inter-individual variability in each group was high, with coefficients of variation exceeding 30% and 50%, respectively. Scatterplots showed a significant correlation in both protein and MUC5AC following collection within a one-hour interval. These data indicate that, regardless of the high inter-individual variability, repeated collection of tear fluid within an hour interval produces reproducible intra-individual data in terms of MUC5AC mucin content, and suggest that the normal mucin composition of the tear fluid can be re-established within an hour of the initial collection.
Vingopoulos F, Koulouri I, Miller JB, Vavvas DG. Anatomical and Functional Recovery Kinetics After Epiretinal Membrane Removal. Clin Ophthalmol 2021;15:175-181.Abstract
Purpose: To investigate the nature of anatomical and functional recovery kinetics after epiretinal membrane (ERM) removal. Methods: The records of 42 patients (45 eyes) with idiopathic ERM treated with pars plana vitrectomy and surgical peeling of the ERM performed by a single surgeon at Massachusetts Eye and Ear between 2012 and 2017 were retrospectively reviewed. Outcome measures included spectral domain optical coherence tomography-measured central macular thickness (CMT) pre-operatively and at post-operative day 1, week 1, months 1, 3, 6, 12 and 24 as well as best-corrected visual acuity (BCVA). Correlations between baseline or early values and final anatomical and functional outcomes were investigated. Results: Improvement in CMT was statistically significant after 1 week, 1, 3, 6, 12 and 24 months ( < 0.01). BCVA improvement was statistically significant after 1, 6, 12 and 24 months follow-up (<0.01). The improvement of BCVA and CMT with time was found to be logarithmic (R =0.96, R =0.84) suggesting that early (<30 days) post-operative functional and anatomical changes may be predictive of long-term outcomes. Preoperative BCVA and CMT revealed a weak positive correlation with the respective BCVA and CMT at 24 months (R=0.13 and R=0.16). When plotted as a percentage of the fellow normal eye CMT, first week proportional improvement in CMT from pre-operative baseline was found to be correlated with final CMT proportional decrease (R=0.72) suggesting that first week postoperative CMT could be predictive of final CMT. Conclusion: There is a logarithmic improvement in CMT and BCVA after ERM peel with BCVA improvement following the CMT improvement. Early (less than 30 days) post-operative anatomical changes can be predictive of long-term anatomical outcomes.
Haque M, Xiong X, Lei F, Das JK, Song J. An optimized protocol for the generation of HBV viral antigen-specific T lymphocytes from pluripotent stem cells. STAR Protoc 2021;2(1):100264.Abstract
In T cell-based cancer immunotherapy, tumor antigen (Ag)-specific CD8 cytotoxic T lymphocytes (CTLs) can specifically target tumor Ags on malignant cells. This promising approach drove us to adopt this strategy of T cell transfer (ACT)-based immunotherapy for chronic viral infections. Here, we describe the generation of hepatitis B virus (HBV) Ag-specific CTLs from induced pluripotent stem cells (iPSCs), i.e., iPSC-CTLs. Ag-specific iPSC-CTLs can target HBV Ag cells and infiltrate into the liver to suppress HBV replication in a murine model. For complete details on the use and execution of this protocol, please refer to Haque et al. (2020).
Maleki N, Szabo E, Becerra L, Moulton E, Scrivani SJ, Burstein R, Borsook D. Ictal and interictal brain activation in episodic migraine: Neural basis for extent of allodynia. PLoS One 2021;16(1):e0244320.Abstract
In some patients, migraine attacks are associated with symptoms of allodynia which can be localized (cephalic) or generalized (extracephalic). Using functional neuroimaging and cutaneous thermal stimulation, we aimed to investigate the differences in brain activation of patients with episodic migraine (n = 19) based on their allodynic status defined by changes between ictal and interictal pain tolerance threshold for each subject at the time of imaging. In this prospective imaging study, differences were found in brain activity between the ictal and interictal visits in the brainstem/pons, thalamus, insula, cerebellum and cingulate cortex. Significant differences were also observed in the pattern of activation along the trigeminal pathway to noxious heat stimuli in no allodynia vs. generalized allodynia in the thalamus and the trigeminal nucleus but there were no activation differences in the trigeminal ganglion. The functional magnetic resonance imaging (fMRI) findings provide direct evidence for the view that in migraine patients who are allodynic during the ictal phase of their attacks, the spinal trigeminal nucleus and posterior thalamus become hyper-responsive (sensitized)-to the extent that they mediate cephalic and extracephalic allodynia, respectively. In addition, descending analgesic systems seem as "switched off" in generalized allodynia.
Wu DM, Ji X, Ivanchenko MV, Chung M, Piper M, Rana P, Wang SK, Xue Y, West E, Zhao SR, Xu H, Cicconet M, Xiong W, Cepko CL. Nrf2 overexpression rescues the RPE in mouse models of retinitis pigmentosa. JCI Insight 2021;6(2)Abstract
Nrf2, a transcription factor that regulates the response to oxidative stress, has been shown to rescue cone photoreceptors and slow vision loss in mouse models of retinal degeneration (rd). The retinal pigment epithelium (RPE) is damaged in these models, but whether it also could be rescued by Nrf2 has not been previously examined. We used an adeno-associated virus (AAV) with an RPE-specific (Best1) promoter to overexpress Nrf2 in the RPE of rd mice. Control rd mice showed disruption of the regular array of the RPE, as well as loss of RPE cells. Cones were lost in circumscribed regions within the cone photoreceptor layer. Overexpression of Nrf2 specifically in the RPE was sufficient to rescue the RPE, as well as the disruptions in the cone photoreceptor layer. Electron microscopy showed compromised apical microvilli in control rd mice but showed preserved microvilli in Best1-Nrf2-treated mice. The rd mice treated with Best1-Nrf2 had slightly better visual acuity. Transcriptome profiling showed that Nrf2 upregulates multiple oxidative defense pathways, reversing declines seen in the glutathione pathway in control rd mice. In summary, Nrf2 overexpression in the RPE preserves RPE morphology and survival in rd mice, and it is a potential therapeutic for diseases involving RPE degeneration, including age-related macular degeneration (AMD).
Ambrosio L, Hansen RM, Moskowitz A, Oza A, Barrett D, Manganella J, Medina G, Kawai K, Fulton AB, Kenna M. Dark-adapted threshold and electroretinogram for diagnosis of Usher syndrome. Doc Ophthalmol 2021;143(1):39-51.Abstract
PURPOSE: To determine the utility of ophthalmology evaluation, dark-adapted threshold, and full-field electroretinogram for early detection of Usher syndrome in young patients with bilateral sensorineural hearing loss. METHODS: We identified 39 patients with secure genetic diagnoses of Usher Syndrome. Visual acuity, spherical equivalent, fundus appearance, dark-adapted threshold, and full-field electroretinogram results were summarized and compared to those in a group of healthy controls with normal hearing. In those Usher patients with repeated measures, regression analysis was done to evaluate for change in visual acuity and dark-adapted threshold with age. Spherical equivalent and full-field electroretinogram responses from dark- and light-adapted eyes were evaluated as a function of age. RESULTS: The majority of initial visual acuity and spherical equivalent results were within normal limits for age. Visual acuity and dark-adapted threshold worsened significantly with age in Usher type 1 but not in Usher type 2. At initial test, full-field electroretinogram responses from dark- and light-adapted eyes were abnormal in 53% of patients. Remarkably, nearly half of our patients (17% of Usher type 1 and 30% of Usher type 2) would have been missed by tests of retinal function alone if evaluated before age 10. CONCLUSIONS: Although there is an association of abnormal dark-adapted threshold and full-field electroretinogram at young ages in Usher patients, it appears that a small but important proportion of patients would not be detected by tests of retinal function alone. Thus, genetic testing is needed to secure a diagnosis of Usher syndrome.
Bennett CR, Bex PJ, Merabet LB. Assessing visual search performance using a novel dynamic naturalistic scene. J Vis 2021;21(1):5.Abstract
Daily activities require the constant searching and tracking of visual targets in dynamic and complex scenes. Classic work assessing visual search performance has been dominated by the use of simple geometric shapes, patterns, and static backgrounds. Recently, there has been a shift toward investigating visual search in more naturalistic dynamic scenes using virtual reality (VR)-based paradigms. In this direction, we have developed a first-person perspective VR environment combined with eye tracking for the capture of a variety of objective measures. Participants were instructed to search for a preselected human target walking in a crowded hallway setting. Performance was quantified based on saccade and smooth pursuit ocular motor behavior. To assess the effect of task difficulty, we manipulated factors of the visual scene, including crowd density (i.e., number of surrounding distractors) and the presence of environmental clutter. In general, results showed a pattern of worsening performance with increasing crowd density. In contrast, the presence of visual clutter had no effect. These results demonstrate how visual search performance can be investigated using VR-based naturalistic dynamic scenes and with high behavioral relevance. This engaging platform may also have utility in assessing visual search in a variety of clinical populations of interest.

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