Publications

2020

Ludwig C, Perera C, Myung D, Greven M, Smith S, Chang R, Leng T. Automatic Identification of Referral-Warranted Diabetic Retinopathy Using Deep Learning on Mobile Phone Images. Transl Vis Sci Technol. 2020;9(2):60.
Purpose: To evaluate the performance of a deep learning algorithm in the detection of referral-warranted diabetic retinopathy (RDR) on low-resolution fundus images acquired with a smartphone and indirect ophthalmoscope lens adapter. Methods: An automated deep learning algorithm trained on 92,364 traditional fundus camera images was tested on a dataset of smartphone fundus images from 103 eyes acquired from two previously published studies. Images were extracted from live video screenshots from fundus examinations using a commercially available lens adapter and exported as a screenshot from live video clips filmed at 1080p resolution. Each image was graded twice by a board-certified ophthalmologist and compared to the output of the algorithm, which classified each image as having RDR (moderate nonproliferative DR or worse) or no RDR. Results: In spite of the presence of multiple artifacts (lens glare, lens particulates/smudging, user hands over the objective lens) and low-resolution images achieved by users of various levels of medical training, the algorithm achieved a 0.89 (95% confidence interval [CI] 0.83-0.95) area under the curve with an 89% sensitivity (95% CI 81%-100%) and 83% specificity (95% CI 77%-89%) for detecting RDR on mobile phone acquired fundus photos. Conclusions: The fully data-driven artificial intelligence-based grading algorithm herein can be used to screen fundus photos taken from mobile devices and identify with high reliability which cases should be referred to an ophthalmologist for further evaluation and treatment. Translational Relevance: The implementation of this algorithm on a global basis could drastically reduce the rate of vision loss attributed to DR.
Wang J, Wang X, Gao Y, Lin Z, Chen J, Gigantelli J, Shapiro J, Xie Z, Pierre S. Stress Signal Regulation by Na/K-ATPase As a New Approach to Promote Physiological Revascularization in a Mouse Model of Ischemic Retinopathy. Invest Ophthalmol Vis Sci. 2020;61(14):9.
Purpose: The identification of target pathways to block excessive angiogenesis while simultaneously restoring physiological vasculature is an unmet goal in the therapeutic management of ischemic retinopathies. pNaKtide, a cell-permeable peptide that we have designed by mapping the site of α1 Na/K-ATPase (NKA)/Src binding, blocks the formation of α1 NKA/Src/reactive oxygen species (ROS) amplification loops and restores physiological ROS signaling in a number of oxidative disease models. The aim of this study was to evaluate the importance of the NKA/Src/ROS amplification loop and the effect of pNaKtide in experimental ischemic retinopathy. Methods: Human retinal microvascular endothelial cells (HRMECs) and retinal pigment epithelium (ARPE-19) cells were used to evaluate the effect of pNaKtide on viability, proliferation, and angiogenesis. Retinal toxicity and distribution were assessed in those cells and in the mouse. Subsequently, the role and molecular mechanism of NKA/Src in ROS stress signaling were evaluated biochemically in the retinas of mice exposed to the well-established protocol of oxygen-induced retinopathy (OIR). Finally, pNaKtide efficacy was assessed in this model. Results: The results suggest a key role of α1 NKA in the regulation of ROS stress and the Nrf2 pathway in mouse OIR retinas. Inhibition of α1 NKA/Src by pNaKtide reduced pathologic ROS signaling and restored normal expression of hypoxia-inducible factor 1-α/vascular endothelial growth factor (VEGF). Unlike anti-VEGF agents, pNaKtide did promote retinal revascularization while inhibiting neovascularization and inflammation. Conclusions: Targeting α1 NKA represents a novel strategy to develop therapeutics that not only inhibit neovascularization but also promote physiological revascularization in ischemic eye diseases.
Tecilazich F, Phan T, Simeoni F, Scotti GM, Dagher Z, Lorenzi M. Patrolling Monocytes Are Recruited and Activated by Diabetes to Protect Retinal Microvessels. Diabetes. 2020;69(12):2709–2719.
In diabetes there is a long latency between the onset of hyperglycemia and the appearance of structural microangiopathy. Because Ly6C patrolling monocytes (PMo) behave as housekeepers of the vasculature, we tested whether PMo protect microvessels against diabetes. We found that in wild-type mice, diabetes reduced PMo in the general circulation but increased by fourfold the absolute number of PMo adherent to retinal vessels (leukostasis). Conversely, in diabetic NR4A1 mice, a model of absence of PMo, there was no increase in leukostasis, and at 6 months of diabetes, the number of retinal acellular capillaries almost doubled compared with diabetic wild-type mice. Circulating PMo showed gene expression changes indicative of enhanced migratory, vasculoprotective, and housekeeping activities, as well as profound suppression of genes related to inflammation and apoptosis. Promigratory CXCR4 was no longer upregulated at longer duration when retinal acellular capillaries begin to increase. Thus, after a short diabetes duration, PMo are the cells preferentially recruited to the retinal vessels and protect vessels from diabetic damage. These observations support the need for reinterpretation of the functional meaning of leukostasis in diabetes and document within the natural history of diabetic retinopathy processes of protection and repair that can provide novel paradigms for prevention.
Georgiou M, Robson A, Fujinami K, Leo SM, Vincent A, Nasser F, Cabral De Guimarães TA, Khateb S, Pontikos N, Fujinami-Yokokawa Y, Liu X, Tsunoda K, Hayashi T, Vargas M, Thiadens A, Carvalho E, Nguyen XTA, Arno G, Mahroo O, Martin-Merida MI, Jimenez-Rolando B, Gordo G, Carreño E, Carmen A, Sharon D, Kohl S, Huckfeldt R, Wissinger B, Boon C, Banin E, Pennesi M, Khan A, Webster A, Zrenner E, Heon E, Michaelides M. KCNV2-associated Retinopathy: Genetics, Electrophysiology and Clinical Course - KCNV2 Study Group Report 1. Am J Ophthalmol. 2020;
PURPOSE: To investigate genetics, electrophysiology and clinical course of KCNV2-associated retinopathy in a cohort of children and adults. STUDY DESIGN: Multicenter international clinical cohort study. METHODS: Review of clinical notes and molecular genetic testing. Full-field electroretinography (ERG) incorporating the international standards were reviewed and quantified and compared with age and recordings from control subjects. RESULTS: In total 230 disease-associated alleles were identified from 117 patients, corresponding to 75 different KCNV2 variants, with 28 being novel. The mean age of onset was 3.9 years old. All patients were symptomatic before the age of 12 years (age range: 0-11 years). Decreased visual acuity was present in all patients, and four other symptoms were common: reduced color vision (78.6%), photophobia (53.5%), nyctalopia (43.6%), and nystagmus (38.6%). After a mean follow of 8.4 years, the mean best corrected visual acuity (BCVA, ±SD) decreased from 0.81 LogMAR (0.27 LogMAR) to 0.90 LogMAR (0.31 LogMAR). Full-field ERGs showed pathognomonic waveform features. Quantitative assessment revealed a wide range of ERG amplitudes and peak times, with a mean rate of age-associated reduction indistinguishable from the control group. Mean amplitude reductions for the DA 0.01 ERG, DA 10 ERG a-wave, LA30Hz and LA3 ERG b-wave were 55%, 21%, 48% and 74% respectively. Peak times showed stability across 6 decades. CONCLUSION: In KCNV2-retinopathy full-field ERGs are diagnostic, and consistent with largely stable peripheral retinal dysfunction. Report No.1 highlights the severity of the clinical phenotype and established a large cohort of patients, emphasizing the unmet need for trials of novel therapeutics.
Ning K, Song E, Sendayen B, Prosseda P, Chang KC, Ghaffarieh A, Alvarado J, Wang B, Haider K, Berbari N, Hu Y, Sun Y. Defective INPP5E distribution in NPHP1-related Senior-Loken syndrome. Mol Genet Genomic Med. 2020;:e1566.
BACKGROUND: Senior-Loken syndrome is a rare genetic disorder that presents with nephronophthisis and retinal degeneration, leading to end-stage renal disease and progressive blindness. The most frequent cause of juvenile nephronophthisis is a mutation in the nephronophthisis type 1 (NPHP1) gene. NPHP1 encodes the protein nephrocystin-1, which functions at the transition zone (TZ) of primary cilia. METHODS: We report a 9-year-old Senior-Loken syndrome boy with NPHP1 deletion, who presents with bilateral vision decrease and cystic renal disease. Renal function deteriorated to require bilateral nephrectomy and renal transplant. We performed immunohistochemistry, H&E staining, and electron microscopy on the renal sample to determine the subcellular distribution of ciliary proteins in the absence of NPHP1. RESULTS: Immunohistochemistry and electron microscopy of the resected kidney showed disorganized cystic structures with loss of cilia in renal tubules. Phosphoinositides have been recently recognized as critical components of the ciliary membrane and immunostaining of kidney sections for phosphoinositide 5-phosphatase, INPP5E, showed loss of staining compared to healthy control. Ophthalmic examination showed decreased electroretinogram consistent with early retinal degeneration. CONCLUSION: The decreased expression of INPP5E specifically in the primary cilium, coupled with disorganized cilia morphology, suggests a novel role of NPHP1 that it is involved in regulating ciliary phosphoinositide composition in the ciliary membrane of renal tubular cells.
Dee EC, Mitchell WG, D’Amico A. Enabling hope. Lancet Oncol. 2020;21(12):e549.
Singh T, Ichhpujani P, Singh RB. First Line of Defense in COVID-19: Masks in Clinical Practice. Asia Pac J Public Health. 2020;:1010539520979928.
The current evidence suggests that masks are efficacious in limiting the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). Although cloth masks are effective in outdoor environments, there is a consensus about the requirement of N95 masks or respirators when working in close proximity to patients who may be asymptomatic carriers, specifically in ophthalmology clinics, where slit-lamp examinations, noncontact tonometry, and other procedures place the physicians and patients in close proximity with each other. In this report, we review the available evidence regarding the efficacy of different types of masks in clinical practice in ophthalmology.
Mitchell W, Hassall M, Henderson T. Updating the model of eye care for Aboriginal populations in remote Central Australia. Clin Exp Ophthalmol. 2020;48(9):1299–1306.
Eye disease is the third-highest contributor towards health inequality for Aboriginal Australians. Understanding how the Central Australian ophthalmology service addresses complexities of remote eye care is crucial in understanding how expansion can meet current and future needs. The present study analyses findings from the MEDLINE database and Governmental reports, and descriptive information from stakeholders in Central Australia and the Australian Department of Health. We describe the current Central Australian ophthalmology model at three levels; (a) the healthcare service level (specialized primary care, local/outreach optometry and ophthalmology services, and intensive extended surgical weeks), (b) the community level (local community staff, clinics and initiatives, and eye "champions" and mutual support), and (c) the healthcare system level (federal and state government, and private funding). We conclude that building full-time specialist availability, and system-wide approaches to increase patient utilisation, will facilitate overcoming barriers of remoteness, and create enduring improvements in Central Australian eye care and health-inequality.
Sobrin L, Yu Y, Susarla G, Chan W, Xia T, Kempen J, Hubbard R, VanderBeek B. Risk of Noninfectious Uveitis with Female Hormonal Therapy in a Large Healthcare Claims Database. Ophthalmology. 2020;127(11):1558–1566.
PURPOSE: To determine if female hormonal therapy (FHT) increases the incidence of noninfectious uveitis. DESIGN: Retrospective cohort study. PARTICIPANTS: Women exposed to FHT and matched women unexposed to FHT enrolled in a national insurance plan. METHODS: Estimation of noninfectious uveitis incidence used multivariable Cox proportional hazards regression. To account for differences between the exposed and unexposed cohorts, a propensity score for being prescribed FHT was created using logistic regression, and inverse probability of treatment weighting was performed. MAIN OUTCOME MEASURES: Incidence of noninfectious uveitis. For the primary outcome, incident noninfectious uveitis was defined as a new diagnosis code for noninfectious uveitis followed by a second instance of a noninfectious uveitis code within 120 days. For the alternative outcome definition, a corticosteroid prescription or code for an ocular corticosteroid injection within 120 days of the uveitis diagnosis code was used instead of the second uveitis diagnosis code. RESULTS: There were 217 653 women exposed to FHT and 928 408 women not unexposed to FHT. For the primary outcome, the hazard ratio (HR) for incident noninfectious uveitis was not significantly different between the FHT and unexposed cohorts (HR, 0.99; 95% confidence interval [CI], 0.83-1.17; P = 0.87). With the alternative outcome definition, the FHT cohort was more likely to develop uveitis (HR, 1.21; 95% CI, 1.04-1.41; P = 0.01). When examined by anatomic subtype, for anterior uveitis there was a greater likelihood of incident uveitis in the exposed cohort (HR, 1.23; 95% CI, 1.05-1.45; P = 0.01) for the alternative outcome definition but not for the primary outcome. With age stratification, women exposed to FHT aged ≥45 years at the time of FHT prescription were more likely to develop uveitis (HR, 1.23; 95% CI, 1.03-1.47; P = 0.03) for the alternative outcome definition. A similar HR (1.22) was seen for women aged ≤44 years at the time of prescription, but this association did not meet statistical significance (P = 0.20). CONCLUSIONS: Exposure to FHT increases the rate of incident noninfectious uveitis when uveitis is defined on the basis of both diagnostic codes and documentation of corticosteroid treatment. However, the risk is modest and FHT is likely safe with regard to noninfectious uveitis risk in the majority of patients exposed to these drugs.
Gilmore M, Salamzade R, Selleck E, Bryan N, Mello S, Manson A, Earl A. Genes Contributing to the Unique Biology and Intrinsic Antibiotic Resistance of Enterococcus faecalis. mBio. 2020;11(6).
The enterococci, which are among the leading causes of multidrug-resistant (MDR) hospital infection, are notable for their environmental ruggedness, which extends to intrinsic antibiotic resistance. To identify genes that confer this unique property, we used Tn-seq to comprehensively explore the genome of MDR strain MMH594 for genes important for growth in nutrient-containing medium and with low-level antibiotic challenge. As expected, a large core of genes for DNA replication, expression, and central metabolism, shared with other bacteria, are intolerant to transposon disruption. However, genes were identified that are important to that are either absent from or unimportant for and fitness when similarly tested. Further, 217 genes were identified that when challenged by sub-MIC antibiotic levels exhibited reduced tolerance to transposon disruption, including those previously shown to contribute to intrinsic resistance, and others not previously ascribed this role. is one of the few Gram-positive bacteria experimentally shown to possess a functional Entner-Doudoroff pathway for carbon metabolism, a pathway that contributes to stress tolerance in other microbes. Through functional genomics and network analysis we defined the unusual structure of this pathway in and assessed its importance. These approaches also identified toxin-antitoxin and related systems that are unique and active in Finally, we identified genes that are absent in the closest nonenterococcal relatives, the vagococci, and that contribute importantly to fitness with and without antibiotic selection, advancing an understanding of the unique biology of enterococci. Enterococci are leading causes of antibiotic-resistant infection transmitted in hospitals. The intrinsic hardiness of these organisms allows them to survive disinfection practices and then proliferate in the gastrointestinal tracts of antibiotic-treated patients. The objective of this study was to identify the underlying genetic basis for its unusual hardiness. Using a functional genomic approach, we identified traits and pathways of general importance for enterococcal survival and growth that distinguish them from closely related pathogens as well as ancestrally related species. We further identified unique traits that enable them to survive antibiotic challenge, revealing a large set of genes that contribute to intrinsic antibiotic resistance and a smaller set of uniquely important genes that are rare outside enterococci.