Immune checkpoint inhibitors and corneal transplant rejection: a call for awareness. Immunotherapy 2020;12(13):947-949..
Ciprofloxacin-loaded bioadhesive hydrogels for ocular applications. Biomater Sci 2020;8(18):5196-5209.Abstract.
The management of corneal infections often requires complex therapeutic regimens involving the prolonged and high-frequency application of antibiotics that provide many challenges to patients and impact compliance with the therapeutic regimens. In the context of severe injuries that lead to tissue defects (e.g. corneal lacerations) topical drug regimens are inadequate and suturing is often indicated. There is thus an unmet need for interventions that can provide tissue closure while concurrently preventing or treating infection. In this study, we describe the development of an antibacterial bioadhesive hydrogel loaded with micelles containing ciprofloxacin (CPX) for the management of corneal injuries at risk of infection. The in vitro release profile showed that the hydrogel system can release CPX, a broad-spectrum antibacterial drug, for up to 24 h. Moreover, the developed CPX-loaded hydrogels exhibited excellent antibacterial properties against Staphylococcus aureus and Pseudomonas aeruginosa, two bacterial strains responsible for the most ocular infections. Physical characterization, as well as adhesion and cytocompatibility tests, were performed to assess the effect of CPX loading in the developed hydrogel. Results showed that CPX loading did not affect stiffness, adhesive properties, or cytocompatibility of hydrogels. The efficiency of the antibacterial hydrogel was assessed using an ex vivo model of infectious pig corneal injury. Corneal tissues treated with the antibacterial hydrogel showed a significant decrease in bacterial colony-forming units (CFU) and a higher corneal epithelial viability after 24 h as compared to non-treated corneas and corneas treated with hydrogel without CPX. These results suggest that the developed adhesive hydrogel system presents a promising suture-free solution to seal corneal wounds while preventing infection.
The effects of age on the contributions of head and eye movements to scanning behavior at intersections. Transp Res Part F Traffic Psychol Behav 2020;73:128-142.Abstract.
The current study was aimed at evaluating the effects of age on the contributions of head and eye movements to scanning behavior at intersections. When approaching intersections, a wide area has to be scanned requiring large lateral head rotations as well as eye movements. Prior research suggests older drivers scan less extensively. However, due to the wide-ranging differences in methodologies and measures used in prior research, the extent to which age-related changes in eye or head movements contribute to these deficits is unclear. Eleven older (mean 67 years) and 18 younger (mean 27 years) current drivers drove in a simulator while their head and eye movements were tracked. Scans, analyzed for 15 four-way intersections in city drives, were split into two categories: (consisting only of eye movements) and (containing both head and eye movements). Older drivers made smaller scans than younger drivers (46.6° vs. 53°), as well as smaller scans (9.2° vs. 10.1°), resulting in overall smaller scans. For scans, older drivers had both a smaller head and a smaller eye movement component. Older drivers made more scans than younger drivers (7 vs. 6) but fewer scans (2.1 vs. 2.7). This resulted in no age effects when considering scans. Our results clarify the contributions of eye and head movements to age-related deficits in scanning at intersections, highlight the importance of analyzing both eye and head movements, and suggest the need for older driver training programs that emphasize the importance of making large scans before entering intersections.
Strengthening the integration of eye care into the health system: methodology for the development of the WHO package of eye care interventions. BMJ Open Ophthalmol 2020;5(1):e000533.Abstract.
Objective: To describe the rational for, and the methods that will be employed to develop, the WHO package of eye care interventions (PECI). Methods and analysis: The development of the package will be conducted in four steps: (1) selection of eye conditions (for which interventions will be included in the package) based on epidemiological data on the causes of vision impairment and blindness, prevalence estimates of eye conditions and health facility data; (2) identification of interventions and related evidence for the selected eye conditions from clinical practice guidelines and high-quality systematic reviews by a technical working group; (3) expert agreement on the inclusion of eye care interventions in the package and the description of resources required for the provision of the selected interventions; and (4) peer review. The project will be led by the WHO Vision Programme in collaboration with Cochrane Eyes and Vision. A Technical Advisory Group, comprised of public health and clinical experts in the field, will provide technical input throughout all stages of development. Results: After considering the feedback of Technical Advisory Group members and reviewing-related evidence, a final list of eye conditions for which interventions will be included in the package has been collated. Conclusion: The PECI will support Ministries of Health in prioritising, planning, budgeting and integrating eye care interventions into health systems. It is anticipated that the PECI will be available for use in 2021.
Glycolysis links reciprocal activation of myeloid cells and endothelial cells in the retinal angiogenic niche. Sci Transl Med 2020;12(555)Abstract.
The coordination of metabolic signals among different cellular components in pathological retinal angiogenesis is poorly understood. Here, we showed that in the pathological angiogenic vascular niche, retinal myeloid cells, particularly macrophages/microglia that are spatially adjacent to endothelial cells (ECs), are highly glycolytic. We refer to these macrophages/microglia that exhibit a unique angiogenic phenotype with increased expression of both M1 and M2 markers and enhanced production of both proinflammatory and proangiogenic cytokines as pathological retinal angiogenesis-associated glycolytic macrophages/microglia (PRAGMs). The phenotype of PRAGMs was recapitulated in bone marrow-derived macrophages or retinal microglia stimulated by lactate that was produced by hypoxic retinal ECs. Knockout of 6-phosphofructo-2-kinase/fructose-2, 6-bisphosphatase (; for rodents), a glycolytic activator in myeloid cells, impaired the ability of macrophages/microglia to acquire an angiogenic phenotype, rendering them unable to promote EC proliferation and sprouting and pathological neovascularization in a mouse model of oxygen-induced proliferative retinopathy. Mechanistically, hyperglycolytic macrophages/microglia produced large amount of acetyl-coenzyme A, leading to histone acetylation and PRAGM-related gene induction, thus reprogramming macrophages/microglia into an angiogenic phenotype. These findings reveal a critical role of glycolytic metabolites as initiators of reciprocal activation of macrophages/microglia and ECs in the retinal angiogenic niche and suggest that strategies targeting the metabolic communication between these cell types may be efficacious in the treatment of pathological retinal angiogenesis.
An Ex Vivo Choroid Sprouting Assay of Ocular Microvascular Angiogenesis. J Vis Exp 2020;(162)Abstract.
Pathological choroidal angiogenesis, a salient feature of age-related macular degeneration, leads to vision impairment and blindness. Endothelial cell (EC) proliferation assays using human retinal microvascular endothelial cells (HRMECs) or isolated primary retinal ECs are widely used in vitro models to study retinal angiogenesis. However, isolating pure murine retinal endothelial cells is technically challenging and retinal ECs may have different proliferation responses than choroidal endothelial cells and different cell/cell interactions. A highly reproducible ex vivo choroidal sprouting assay as a model of choroidal microvascular proliferation was developed. This model includes the interaction between choroid vasculature (EC, macrophages, pericytes) and retinal pigment epithelium (RPE). Mouse RPE/choroid/scleral explants are isolated and incubated in growth-factor-reduced basal membrane extract (BME) (day 0). Medium is changed every other day and choroid sprouting is quantified at day 6. The images of individual choroid explant are taken with an inverted phase microscope and the sprouting area is quantified using a semi-automated macro plug-in to the ImageJ software developed in this lab. This reproducible ex vivo choroidal sprouting assay can be used to assess compounds for potential treatment and for microvascular disease research to assess pathways involved in choroidal micro vessel proliferation using wild type and genetically modified mouse tissue.
Recalcitrant Macular Hole Closure by Autologous Retinal Transplant Using the Peripheral Retina. Clin Ophthalmol 2020;14:2301-2306.Abstract.
Purpose: The peripheral adult human retina has been found to contain neuroepithelial stem cells. In this study, we examined the efficacy of an auto-transplant of peripheral retina into refractory macular holes (MH) from both anatomic and physiologic perspectives. Methods: The population consisted of four female patients aged 72, 82, 65 and 84 years (cases 1-4, respectively) with persistent refractory MH status; internal limiting membrane (ILM) peeling (case 1), ILM transplant (case 2), and inverted ILM (cases 3 and 4 with myopic MH). In all our cases, retinal grafts were harvested beyond the equator from the far retinal periphery using curved horizontal scissors and gently moved toward the MH using a forceps. A 25-G manipulator with a silicone ball tip was used to tuck the trimmed graft into the MH, followed by fluid-air exchange and infusion of silicone oil, which was removed three months later. Results: Partial restoration and integration of the outer retinal layer were confirmed on an OCT-B scan imaging. The visual acuity (VA) was improved in all cases: 1.2 to 1.0 logMAR (case 1), 2.0 to 1.3 logMAR (case 2), 2.3 to 1.4 logMAR (case 3) and 2.0 to 1.0 logMAR (case 4). Microperimetry showed improved retinal sensitivity in every case. No intra- or post-operative complications were observed. Conclusion: Under pathological conditions, the Müller glia reportedly serves as a source of neuronal progenitor cells in regenerating retina, continuing to divide and migrate to the outer nuclear layer thus replacing lost photo-receptors. Although the histological findings remain unknown, the positive anatomic and physiologic outcomes of the auto-transplanted retinal flap in our series suggest that this technique may offer an effective option for treating recalcitrant MH. Further studies are warranted.
Recurrent Rare Copy Number Variants Increase Risk for Esotropia. Invest Ophthalmol Vis Sci 2020;61(10):22.Abstract.
Purpose: To determine whether rare copy number variants (CNVs) increase risk for comitant esotropia. Methods: CNVs were identified in 1614 Caucasian individuals with comitant esotropia and 3922 Caucasian controls from Illumina SNP genotyping using two Hidden Markov model (HMM) algorithms, PennCNV and QuantiSNP, which call CNVs based on logR ratio and B allele frequency. Deletions and duplications greater than 10 kb were included. Common CNVs were excluded. Association testing was performed with 1 million permutations in PLINK. Significant CNVs were confirmed with digital droplet polymerase chain reaction (ddPCR). Whole genome sequencing was performed to determine insertion location and breakpoints. Results: Esotropia patients have similar rates and proportions of CNVs compared with controls but greater total length and average size of both deletions and duplications. Three recurrent rare duplications significantly (P = 1 × 10-6) increase the risk of esotropia: chromosome 2p11.2 (hg19, 2:87428677-87965359), spanning one long noncoding RNA (lncRNA) and two microRNAs (OR 14.16; 95% confidence interval [CI] 5.4-38.1); chromosome 4p15.2 (hg19, 4:25554332-25577184), spanning one lncRNA (OR 11.1; 95% CI 4.6-25.2); chromosome 10q11.22 (hg19, 10:47049547-47703870) spanning seven protein-coding genes, one lncRNA, and four pseudogenes (OR 8.96; 95% CI 5.4-14.9). Overall, 114 cases (7%) and only 28 controls (0.7%) had one of the three rare duplications. No case nor control had more than one of these three duplications. Conclusions: Rare CNVs are a source of genetic variation that contribute to the genetic risk for comitant esotropia, which is likely polygenic. Future research into the functional consequences of these recurrent duplications may shed light on the pathophysiology of esotropia.
Evaluating Goldmann Applanation Tonometry Intraocular Pressure Measurement Agreement Between Ophthalmic Technicians and Physicians. Am J Ophthalmol 2020;219:170-176.Abstract.
PURPOSE: To examine IOP measurement disagreement between technicians and physicians and the impact of an educational intervention on the short and long-term disagreement in IOP measurement using Goldmann applanation tonometry. DESIGN: Prospective study designed to enhance measurement reliability. SETTING: A glaucoma clinic at a university hospital. StudyPopulation: 6 technicians and 2 physicians. INTERVENTION: An educational intervention was implemented for the technicians to improve IOP measurement agreement with physicians. MainOutcomeMeasures: Frequency of IOP measurement disagreement between physicians and technicians, defined as a difference in IOP of >2 or >3 mm Hg and assessed at baseline and immediately and 6 months postintervention. RESULTS: IOP was evaluated for a total of 529 eyes (physician measured mean IOP = 16.4 mm Hg [SD = 5.9]), 30 per technician-physician pair for each data collection period: baseline, immediately postintervention and 6 months postintervention. At baseline, physicians disagreed 17% and 7% of the time when measuring IOP using >2 and >3 mm Hg to define disagreement, respectively, whereas the average disagreement between technicians and physicians was 25% and 13%. Disagreement was greater at IOPs greater than 20 mm Hg. No significant changes were noted in the frequency of disagreement between technicians and physicians immediately or 6 months postintervention. CONCLUSIONS: Two physicians measuring the same patient in the same room disagreed by >2 mm Hg in 17% of patients' eyes, and this amount of disagreement was even higher when comparing physicians to certified technicians. An educational intervention did not improve agreement in IOP measurements between technicians and physicians. This highlights an important limitation of Goldmann tonometry.
Advances in Telemedicine in Ophthalmology. Semin Ophthalmol 2020;:1-6.Abstract.
Telemedicine is the provision of healthcare-related services from a distance and is poised to move healthcare from the physician's office back into the patient's home. The field of ophthalmology is often at the forefront of technological advances in medicine including telemedicine and the use of artificial intelligence. Multiple studies have demonstrated the reliability of tele-ophthalmology for use in screening and diagnostics and have demonstrated benefits to patients, physicians, as well as payors. There remain obstacles to widespread implementation, but recent legislation and regulation passed due to the devastating COVID-19 pandemic have helped to reduce some of these barriers. This review describes the current status of tele-ophthalmology in the United States including benefits, hurdles, current programs, technology, and developments in artificial intelligence. With ongoing advances patients may benefit from improved detection and earlier treatment of eye diseases, resulting in better care and improved visual outcomes.
Integrin: Basement membrane adhesion by corneal epithelial and endothelial cells. Exp Eye Res 2020;:108138.Abstract.
Integrins mediate adhesion of cells to substrates and maintain tissue integrity by facilitating mechanotransduction between cells, the extracellular matrix, and gene expression in the nucleus. Changes in integrin expression in corneal epithelial cells and corneal endothelial cells impacts their adhesion to the epithelial basement membrane (EpBM) and Descemet's membrane, respectively. Integrins also play roles in assembly of basement membranes by both activating TGFβ1 and other growth factors. Over the past two decades, this knowledge has been translated into methods to grow corneal epithelial and endothelial cells in vitro for transplantation in the clinic thereby transforming clinical practice and quality of life for patients. Current knowledge on the expression and function of the integrins that mediate adhesion to the basement membrane expressed by corneal epithelial and endothelial cells in health and disease is summarized. This is the first review to discuss similarities and differences in the integrins expressed by both cell types.
Severe bilateral ankyloblepharon filiforme adnatum. J AAPOS 2020;Abstract.
We present a case of bilateral ankyloblepharon filiforme adnatum in 1-day-old girl and describe our surgical approach. The bands connecting the upper and lower eyelids of both eyes were severed using blunt scissors. Point bleeding at the cut bands stopped in 1-2 minutes, without the need for cauterization or compression. The patient was able to open her eyes shortly after the procedure, as she woke up from anesthesia. Examination under general anesthesia showed normal eye examination appropriate for age. Postoperatively, the patient maintained open palpebral fissures. Visual development over 3 years' follow-up was normal.
Convolutional Neural Networks Can Predict Retinal Differentiation in Retinal Organoids. Front Cell Neurosci 2020;14:171.Abstract.
We have developed a deep learning-based computer algorithm to recognize and predict retinal differentiation in stem cell-derived organoids based on bright-field imaging. The three-dimensional "organoid" approach for the differentiation of pluripotent stem cells (PSC) into retinal and other neural tissues has become a major strategy to recapitulate development. We decided to develop a universal, robust, and non-invasive method to assess retinal differentiation that would not require chemical probes or reporter gene expression. We hypothesized that basic-contrast bright-field (BF) images contain sufficient information on tissue specification, and it is possible to extract this data using convolutional neural networks (CNNs). Retina-specific Rx-green fluorescent protein mouse embryonic reporter stem cells have been used for all of the differentiation experiments in this work. The BF images of organoids have been taken on day 5 and fluorescent on day 9. To train the CNN, we utilized a transfer learning approach: ImageNet pre-trained ResNet50v2, VGG19, Xception, and DenseNet121 CNNs had been trained on labeled BF images of the organoids, divided into two categories (retina and non-retina), based on the fluorescent reporter gene expression. The best-performing classifier with ResNet50v2 architecture showed a receiver operating characteristic-area under the curve score of 0.91 on a test dataset. A comparison of the best-performing CNN with the human-based classifier showed that the CNN algorithm performs better than the expert in predicting organoid fate (84% vs. 67 ± 6% of correct predictions, respectively), confirming our original hypothesis. Overall, we have demonstrated that the computer algorithm can successfully recognize and predict retinal differentiation in organoids before the onset of reporter gene expression. This is the first demonstration of CNN's ability to classify stem cell-derived tissue .
Lacrimal Gland Myoepithelial Cells Are Altered in a Mouse Model of Dry Eye Disease. Am J Pathol 2020;190(10):2067-2079.Abstract.
The purpose of this study was to determine the pathogenic changes that occur in myoepithelial cells (MECs) from lacrimal glands of a mouse model of Sjögren syndrome. MECs were cultured from lacrimal glands of C57BL/6J [wild type (WT)] and thrombospondin 1 null (TSP1, alias Thbs1) mice and from mice expressing α-smooth muscle actin-green fluorescent protein that labels MECs. MECs were stimulated with cholinergic and α-adrenergic agonists, vasoactive intestinal peptide (VIP), and the purinergic agonists ATP and UTP. Then intracellular [Ca] was measured using fura-2, and contraction was observed using live cell imaging. Expression of purinergic receptors was determined by Western blot analysis, and mRNA expression was analyzed by microarray. The increase in intracellular [Ca] with VIP and UTP was significantly smaller in MECs from TSP1 compared with WT mice. Cholinergic agonists, ATP, and UTP stimulated contraction in MECs, although contraction of MECs from TSP1 mice was reduced compared with WT mice. The amount of purinergic receptors P2Y1, P2Y11, and P2Y13 was significantly decreased in MECs from TSP1 compared with WT mice, whereas several extracellular matrix and inflammation genes were up-regulated in MECs from TSP1 mice. We conclude that lacrimal gland MEC function is altered by inflammation because the functions regulated by cholinergic agonists, VIP, and purinergic receptors are decreased in TSP1 compared with WT mice.
Microglia modulation by TGF-β1 protects cones in mouse models of retinal degeneration. J Clin Invest 2020;130(8):4360-4369.Abstract.
Retinitis pigmentosa (RP) is a genetically heterogenous group of eye diseases in which initial degeneration of rods triggers secondary degeneration of cones, leading to significant loss of daylight, color, and high-acuity vision. Gene complementation with adeno-associated viral (AAV) vectors is one strategy to treat RP. Its implementation faces substantial challenges, however; for example, the tremendous number of loci with causal mutations. Gene therapy targeting secondary cone degeneration is an alternative approach that could provide a much-needed generic treatment for many patients with RP. Here, we show that microglia are required for the upregulation of potentially neurotoxic inflammatory factors during cone degeneration in RP, creating conditions that might contribute to cone dysfunction and death. To ameliorate the effects of such factors, we used AAV vectors to express isoforms of the antiinflammatory cytokine transforming growth factor beta (TGF-β). AAV-mediated delivery of TGF-β1 rescued degenerating cones in 3 mouse models of RP carrying different pathogenic mutations. Treatment with TGF-β1 protected vision, as measured by 2 behavioral assays, and could be pharmacologically disrupted by either depleting microglia or blocking the TGF-β receptors. Our results suggest that TGF-β1 may be broadly beneficial for patients with cone degeneration, and potentially other forms of neurodegeneration, through a pathway dependent upon microglia.