Ocular Findings Aid in Diagnosis of West Nile Virus.

INTRODUCTION: West Nile virus disease, which is endemic to the United States, is a rarely reported systemic infection that can be difficult to diagnose. Chorioretinitis is an uncommon manifestation of West Nile virus but has pathognomonic ocular findings that can aid in diagnosis. CASE PRESENTATION: A 66-year-old man presented with acute onset fever, chills, and dyspnea. He underwent an extensive but nondiagnostic workup during hospitalization. New visual complaints prompted ophthalmology consultation. Funduscopic examination showed macular hemorrhages and midperipheral chorioretinal lesions. Fluorescein angiography revealed target-like lesions in a radial distribution, which is pathognomonic for West Nile virus chorioretinitis. Serology confirmed the diagnosis of West Nile virus disease. Systemic and ocular symptoms improved with supportive care. DISCUSSION: West Nile virus disease has many nonspecific manifestations. History of recent mosquito exposure is not always readily elicited. In patients with visual symptoms, eye examination can help in its diagnosis. CONCLUSIONS: West Nile virus should be considered in patients with acute febrile or neurological illness during mosquito season.

Retractable Urology Three-Pronged Grasping Forceps for Removal of Large, Non-Magnetic Intraocular Foreign Bodies.

PURPOSE: To demonstrate the use of urology retractable three-pronged grasping forceps in the removal of a large, round, and non-magnetic intraocular foreign body (IOFB) that was difficult to remove with other surgical instruments. METHODS: Extraction of a 3.0 mm lead shot pellet embedded in vitreous hemorrhage was attempted with multiple surgical instruments including an intraocular magnet, IOFB forceps, and two tools designed for urology stone removal: a three-pronged grasping forceps and a nitinol basket extractor. RESULTS: Due to the round and smooth surface, large size, and non-magnetic nature of the IOFB, extraction was challenging and failed with multiple other surgical instruments. The wide and secure grasp of the grasping forceps allowed for swift IOFB extraction without iatrogenic injury to the retina. CONCLUSION: The grasping forceps offer an effective and safe method for removal of large, round, and non-magnetic IOFBs.

GM3 synthase deficiency increases brain glucose metabolism in mice.

GM3 synthase (GM3S) deficiency is a rare neurodevelopmental disorder caused by an inability to synthesize gangliosides, for which there is currently no treatment. Gangliosides are brain-enriched, plasma membrane glycosphingolipids with poorly understood biological functions related to cell adhesion, growth, and receptor-mediated signal transduction. Here, we investigated the effects of GM3S deficiency on metabolism and mitochondrial function in a mouse model. By indirect calorimetry, GM3S knockout mice exhibited increased whole-body respiration and an increased reliance upon carbohydrate as an energy source. 18F-FDG PET confirmed higher brain glucose uptake in knockout mice, and GM3S deficient N41 neuronal cells showed higher glucose utilization in vitro. Brain mitochondria from knockout mice respired at a higher rate on Complex I substrates including pyruvate. This appeared to be due to higher expression of pyruvate dehydrogenase (PDH) and lower phosphorylation of PDH, which would favor pyruvate entry into the mitochondrial TCA cycle. Finally, it was observed that blocking glucose metabolism with the glycolysis inhibitor 2-deoxyglucose reduced seizure intensity in GM3S knockout mice following administration of kainate. In conclusion, GM3S deficiency may be associated with a hypermetabolic phenotype that could promote seizure activity.

Human Monoclonal Antibodies to Escherichia coli Outer Membrane Protein A Porin Domain Cause Aggregation but Do Not Alter In Vivo Bacterial Burdens in a Murine Sepsis Model.

Escherichia coli is one of the most frequent human pathogens, increasingly exhibits antimicrobial resistance, and has complex interactions with the host immune system. E. coli exposure or infection can result in the generation of antibodies specific for outer membrane protein A (OmpA), a multifunctional porin. We identified four OmpA-specific naturally occurring antibodies from healthy human donor B cells and assessed their interactions with E. coli and OmpA. These antibodies are highly specific for OmpA, exhibiting no cross-reactivity to a strain lacking ompA and retaining binding to both laboratory and clinical isolates of E. coli in enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assays. One monoclonal antibody (Mab), designated ECOL-11, is specific for the extracellular N-terminal porin domain of OmpA and induces growth phase-specific bacterial aggregation. This aggregation is not induced by the fragment antigen binding (Fab) form of the MAb, suggesting the importance of bivalency for this aggregating activity. ECOL-11 decreases adhesion and phagocytosis of E. coli by RAW 264.7 macrophage-like cells, possibly by inhibiting the adhesion functions of OmpA. Despite this in vitro phenotype, organ E. coli burdens were not altered by antibody prophylaxis in a murine model of lethal E. coli septic shock. Our findings support the importance of OmpA at the host-pathogen interface and begin to explore the implications and utility of E. coli-specific antibodies in human hosts.

Quiz-Based Microlearning at Scale: a Rapid Educational Response to COVID-19.

Virtual quizzing is a viable model for continuing education at a large scale, particularly during the COVID-19 pandemic. By leveraging technology, microlearning encourages mobile education that is engaging, flexible, and accessible. Learners reported that this format was effective and preferable to traditional methods of education, suggesting further opportunity for innovation.

Alu complementary DNA is enriched in atrophic macular degeneration and triggers retinal pigmented epithelium toxicity via cytosolic innate immunity.

Long interspersed nuclear element-1 (L1)­mediated reverse transcription (RT) of Alu RNA into cytoplasmic Alu complementary DNA (cDNA) has been implicated in retinal pigmented epithelium (RPE) degeneration. The mechanism of Alu cDNA­induced cytotoxicity and its relevance to human disease are unknown. Here we report that Alu cDNA is highly enriched in the RPE of human eyes with geographic atrophy, an untreatable form of age-related macular degeneration. We demonstrate that the DNA sensor cGAS engages Alu cDNA to induce cytosolic mitochondrial DNA escape, which amplifies cGAS activation, triggering RPE degeneration via the inflammasome. The L1-extinct rice rat was resistant to Alu RNA­induced Alu cDNA synthesis and RPE degeneration, which were enabled upon L1-RT overexpression. Nucleoside RT inhibitors (NRTIs), which inhibit both L1-RT and inflammasome activity, and NRTI derivatives (Kamuvudines) that inhibit inflammasome, but not RT, both block Alu cDNA toxicity, identifying inflammasome activation as the terminal effector of RPE degeneration.

Case report: Vitreous hemorrhage as the presenting sign of retinal cavernous hemangioma in a newborn.

PURPOSE: To report a case of vitreous hemorrhage as the presenting sign of retinal cavernous hemangioma (RCH) in a newborn. OBSERVATIONS: A five-week-old full-term male with a history of seizures and birth trauma underwent ophthalmology screening. Initial eye examination revealed vitreous hemorrhage. Subsequent examination under anesthesia with multi-modal imaging revealed vitreous hemorrhage and an intra-retinal mass with numerous sac-like aneurysmal dilatations, consistent with RCH. CONCLUSIONS AND IMPORTANCE: Vitreous hemorrhage in a neonate is an atypical presentation of RCH. Clinicians should be aware that birth trauma may lead to vitreous hemorrhage from RCH. This is the first description of RCH, a rare retinal vascular tumor, in a newborn.

Postoperative Endophthalmitis Caused by Cutibacterium (Formerly Propionibacterium) Acnes: Case Series and Review.

We report the clinical features, treatment strategies and outcomes in a series of patients with infectious endophthalmitis after cataract surgery caused by Cutibacterium acnes (C. acnes), formerly known as Propionibacterium acnes (P. acnes). This retrospective case series includes six eyes of six patients with chronic postoperative endophthalmitis caused by culture-proven C. acnesfrom December 2010 to July 2019 at a University referral center. All patients underwent prior cataract extraction with intraocular lens (CE/IOL) implantation. The mean time between cataract surgery and the microbiologic diagnosis of endophthalmitis was 7.4 ± 5.2 months (range 1.5-17 months). The average time from obtaining the specimen to culture positivity was 7.7 ± 4.4 days (range 3-15 days). Three eyes (50%) presented with hypopyon and three eyes (50%) presented with prominent keratic precipitates without hypopyon. Presenting visual acuity ranged from 20/25 to 2/200. Initial treatments included intravitreal antibiotics alone (n = 2), pars plana vitrectomy (PPV) with partial capsulectomy and intravitreal antibiotics (n = 3), and pars plana vitrectomy with IOL removal and intravitreal antibiotics (n = 1). Follow-up treatments included IOL removal (n = 2), intravitreal antibiotics (n = 1), and topical antibiotics (n = 1). The best-corrected visual acuity at last follow-up was 20/70 or better in all patients. In a literature review, the clinical features and treatment outcomes for all case series of delayed-onset postoperative endophthalmitis caused by C. acnes(n = 120) are listed. A definitive cure (the absence of recurrent inflammation) was achieved in 100% of patients that underwent IOL removal, in 77% of those that underwent PPV/partial capsulectomy and intravitreal antibiotics, and in 18% of cases treated with intravitreal antibiotics alone. Endophthalmitis after CE/IOL caused by C. acnesis characterized by slowly progressive intraocular inflammation and has a protracted course from surgery to microbiologic diagnosis. Visual outcomes are generally favorable, but IOL explantation may be necessary for definitive cure.

Cytoplasmic synthesis of endogenous Alu complementary DNA via reverse transcription and implications in age-related macular degeneration.

Alu retroelements propagate via retrotransposition by hijacking long interspersed nuclear element-1 (L1) reverse transcriptase (RT) and endonuclease activities. Reverse transcription of Alu RNA into complementary DNA (cDNA) is presumed to occur exclusively in the nucleus at the genomic integration site. Whether Alu cDNA is synthesized independently of genomic integration is unknown. Alu RNA promotes retinal pigmented epithelium (RPE) death in geographic atrophy, an untreatable type of age-related macular degeneration. We report that Alu RNA-induced RPE degeneration is mediated via cytoplasmic L1-reverse-transcribed Alu cDNA independently of retrotransposition. Alu RNA did not induce cDNA production or RPE degeneration in L1-inhibited animals or human cells. Alu reverse transcription can be initiated in the cytoplasm via self-priming of Alu RNA. In four health insurance databases, use of nucleoside RT inhibitors was associated with reduced risk of developing atrophic macular degeneration (pooled adjusted hazard ratio, 0.616; 95% confidence interval, 0.493-0.770), thus identifying inhibitors of this Alu replication cycle shunt as potential therapies for a major cause of blindness.

UV-Photokeratitis Associated with Germicidal Lamps Purchased during the COVID-19 Pandemic.

PURPOSE: To report photokeratitis caused by the improper use of germicidal lamps purchased during the COVID-19 pandemic. METHODS: Case series. RESULTS: Seven patients presented with acute ocular surface pain after exposure to UV-emitting germicidal lamps. Visual acuity was 20/30 or better in 13 of 14 eyes (93%). Anterior segment examination revealed varying degrees of conjunctival injection and diffusely distributed punctate epithelial erosions (PEEs) in every patient. No intraocular inflammation was identified across the cohort and all fundus examinations were normal. Treatment varied by provider and included artificial tears alone or in combination with antibiotic ointments and/or topical steroids. Five patients were followed via telehealth, one patient returned for an in-office visit, and one patient was lost to follow-up. Five of six patients endorsed complete resolution of symptoms within 2-3 days. CONCLUSIONS: Patients should follow manufacturer recommendations when using UV-emitting germicidal lamps and avoid direct exposure to the ocular surface.

Comparison Between Graders in Detection of Diabetic Neovascularization With Swept Source Optical Coherence Tomography Angiography and Fluorescein Angiography.

PURPOSE: We compared the ability of ophthalmologists to identify neovascularization (NV) in patients with proliferative diabetic retinopathy using swept-source optical coherence tomography angiography (SS-OCTA) and fluorescein angiography (FA). DESIGN: Retrospective study comparing diagnostic instruments. METHODS: Eyes with proliferative diabetic retinopathy or severe nonproliferative diabetic retinopathy and a high suspicion of NV based on clinical examination were imaged using SS-OCTA and FA at the same visit. Two separate grading sets consisting of scrambled, anonymized SS-OCTA and FA images were created. The ground truth for presence of NV was established by consensus of 2 graders with OCTA experience who did not participate in the subsequent assessment of NV in this study. The 2 anonymized image sets were graded for presence or absence of NV by 12 other graders that included 2 residents, 6 vitreoretinal fellows, and 4 vitreoretinal attending physicians. The percentage of correct grading of NV using SS-OCTA and FA was assessed for each grader and across grader training levels. RESULTS: Forty-seven eyes from 24 patients were included in this study. Overall, the mean percentage of correct NV grading was 87.8% using SS-OCTA with B-scans and 86.2% using FA (P = .92). Assessing each grader individually, there was no statistically significant asymmetry in correct grading using SS-OCTA and FA. CONCLUSIONS: Ophthalmologists across training levels were able to identify diabetic NV with equal accuracy using SS-OCTA and FA. Based on these results, SS-OCTA may be an appropriate standalone modality for diagnosing diabetic NV.

Sixth Cranial Nerve Palsy as the Presenting Sign of Metastatic Cholangiocarcinoma.

BACKGROUND: Cholangiocarcinoma is a locally invasive, poorly treatable malignancy of the biliary tract that uncommonly metastasizes to the brain and rarely causes neuro-ophthalmologic complications. CASE PRESENTATION: A 34-year-old woman with an isolated sixth cranial nerve palsy underwent brain neuroimaging and was found to have a large sellar/suprasellar mass invading the cavernous sinus. Gross total resection was performed with improvement in the sixth cranial nerve nerve palsy. Next-generation sequencing and histology studies revealed an adenocarcinoma with a fibroblast growth factor receptor (FGFR)2-BICC1 gene mutation. Positron emission tomography/computed tomography scan demonstrated a large hypermetabolic partially necrotic hepatic mass with local invasion, and liver biopsy confirmed a diagnosis of cholangiocarcinoma. At three weeks after resection, the brain lesion recurred and the patient developed worsening diplopia. The patient then received stereotactic radiotherapy applied to the brain lesion and began treatment with gemcitabine and cisplatin. The patient was transitioned to FGFR-targeted therapy with pemigatinib, and the patient was alive at last follow-up, 49 weeks after diagnosis. CONCLUSION: To our knowledge, this is the first report of cholangiocarcinoma presenting as a neuro-ophthalmologic finding, consisting of an isolated sixth cranial nerve palsy, which was the harbinger of a brain metastatic sellar/suprasellar mass. The case highlights the importance of prompt neuroimaging in isolated cranial nerve palsies, particularly in younger patients, and consideration of rare aggressive metastasis to the sellar region, where prompt surgery and pathology are critical in identifying the primary carcinoma and to instituting expedited therapy.

Repurposing anti-inflammasome NRTIs for improving insulin sensitivity and reducing type 2 diabetes development.

Innate immune signaling through the NLRP3 inflammasome is activated by multiple diabetes-related stressors, but whether targeting the inflammasome is beneficial for diabetes is still unclear. Nucleoside reverse-transcriptase inhibitors (NRTI), drugs approved to treat HIV-1 and hepatitis B infections, also block inflammasome activation. Here, we show, by analyzing five health insurance databases, that the adjusted risk of incident diabetes is 33% lower in patients with NRTI exposure among 128,861 patients with HIV-1 or hepatitis B (adjusted hazard ratio for NRTI exposure, 0.673; 95% confidence interval, 0.638 to 0.710; P < 0.0001; 95% prediction interval, 0.618 to 0.734). Meanwhile, an NRTI, lamivudine, improves insulin sensitivity and reduces inflammasome activation in diabetic and insulin resistance-induced human cells, as well as in mice fed with high-fat chow; mechanistically, inflammasome-activating short interspersed nuclear element (SINE) transcripts are elevated, whereas SINE-catabolizing DICER1 is reduced, in diabetic cells and mice. These data suggest the possibility of repurposing an approved class of drugs for prevention of diabetes.

Chronic Dicer1 deficiency promotes atrophic and neovascular outer retinal pathologies in mice.

Degeneration of the retinal pigmented epithelium (RPE) and aberrant blood vessel growth in the eye are advanced-stage processes in blinding diseases such as age-related macular degeneration (AMD), which affect hundreds of millions of people worldwide. Loss of the RNase DICER1, an essential factor in micro-RNA biogenesis, is implicated in RPE atrophy. However, the functional implications of DICER1 loss in choroidal and retinal neovascularization are unknown. Here, we report that two independent hypomorphic mouse strains, as well as a separate model of postnatal RPE-specific DICER1 ablation, all presented with spontaneous RPE degeneration and choroidal and retinal neovascularization. DICER1 hypomorphic mice lacking critical inflammasome components or the innate immune adaptor MyD88 developed less severe RPE atrophy and pathological neovascularization. DICER1 abundance was also reduced in retinas of the JR5558 mouse model of spontaneous choroidal neovascularization. Finally, adenoassociated vector-mediated gene delivery of a truncated DICER1 variant (OptiDicer) reduced spontaneous choroidal neovascularization in JR5558 mice. Collectively, these findings significantly expand the repertoire of DICER1 in preserving retinal homeostasis by preventing both RPE degeneration and pathological neovascularization.

Latent Sensitization in a Mouse Model of Ocular Neuropathic Pain.

PURPOSE: Chronic ocular pain is poorly understood and difficult to manage. We developed a murine model of corneal surface injury (CSI)-induced chronic ocular neuropathic pain. The study focuses on changes in corneal nerve morphology and associated short- and long-term pain-like behavior after CSI. METHODS: CSI was induced in mice by local application of an alkali solution (0.75 N NaOH). Corneal nerve architecture, morphology, density, and length were studied. Eye-wiping was evaluated before and after CSI in response to hypertonic saline (2 M NaCl). Naltrexone (NTX) or Naloxone-methiodide (NLX-me), opioid receptor antagonists, were given subcutaneously (s.c., 3 mg/kg) or topically (eye drop, 100 µM), and then an eye-wiping test was performed. RESULTS: CSI caused partial corneal deinnervation followed by gradual reinnervation. Regenerated nerves displayed increased tortuosity, beading, and branching. CSI enhanced hypertonic saline-induced eye-wiping behavior compared to baseline or sham-injury (P < 0.01). This hypersensitivity peaked at 10 days and subsided 14 days after CSI. Administration of NTX, or NLX-me, a selective peripheral opioid antagonist, reinstated eye-wiping behavior in the injury group, but not in the sham groups (P < 0.05). CONCLUSIONS: This study introduces a model of chronic ocular pain and corneal neuropathy following CSI. CSI induces central and peripheral opioid receptor-dependent latent sensitization (LS) that is unmasked by systemic or topical administration of opioid antagonists. TRANSLATIONAL RELEVANCE: This model of chronic ocular pain establishes LS as a new inhibitory mechanism in the oculotrigeminal system and may be used for potential diagnostic and therapeutic interventions for ocular neuropathy.

cGAS drives noncanonical-inflammasome activation in age-related macular degeneration.

Geographic atrophy is a blinding form of age-related macular degeneration characterized by retinal pigmented epithelium (RPE) death; the RPE also exhibits DICER1 deficiency, resultant accumulation of endogenous Alu-retroelement RNA, and NLRP3-inflammasome activation. How the inflammasome is activated in this untreatable disease is largely unknown. Here we demonstrate that RPE degeneration in human-cell-culture and mouse models is driven by a noncanonical-inflammasome pathway that activates caspase-4 (caspase-11 in mice) and caspase-1, and requires cyclic GMP-AMP synthase (cGAS)-dependent interferon-ß production and gasdermin D-dependent interleukin-18 secretion. Decreased DICER1 levels or Alu-RNA accumulation triggers cytosolic escape of mitochondrial DNA, which engages cGAS. Moreover, caspase-4, gasdermin D, interferon-ß, and cGAS levels were elevated in the RPE in human eyes with geographic atrophy. Collectively, these data highlight an unexpected role of cGAS in responding to mobile-element transcripts, reveal cGAS-driven interferon signaling as a conduit for mitochondrial-damage-induced inflammasome activation, expand the immune-sensing repertoire of cGAS and caspase-4 to noninfectious human disease, and identify new potential targets for treatment of a major cause of blindness.