Wang JC, Miller JB. For Mass Eye and Ear Special Issue: Optical Coherence Tomography Angiography: Review of Current Technical Aspects and Applications in Chorioretinal Disease. Semin Ophthalmol 2019;:1-7.Abstract
Optical coherence tomography angiography (OCT-A) has enabled fast, non-invasive, high-resolution visualization of vasculature within the eye. In the past few years, it has become increasingly utilized for a range of disorders including age-related macular degeneration, diabetic retinopathy, retinal vein occlusions, and uveitis among others. This article reviews technical aspects of OCT-A, its applications in chorioretinal disease, and known limitations of the technology.
Rosales MAB, Shu DY, Iacovelli J, Saint-Geniez M. Loss of PGC-1α in RPE induces mesenchymal transition and promotes retinal degeneration. Life Sci Alliance 2019;2(3)Abstract
The retinal pigment epithelium (RPE) supports visual processing and photoreceptor homeostasis via energetically demanding cellular functions. Here, we describe the consequences of repressing peroxisome proliferator-activated receptor γ coactivator-1 α (PGC-1α), a master regulator of mitochondrial function and biogenesis, on RPE epithelial integrity. The sustained silencing of PGC-1α in differentiating human RPE cells affected mitochondria/autophagy function, redox state, and impaired energy sensor activity ultimately inducing epithelial to mesenchymal transition (EMT). Adult conditional knockout of PGC-1 coactivators in mice resulted in rapid RPE dysfunction and transdifferentiation associated with severe photoreceptor degeneration. RPE anomalies were characteristic of autophagic defect and mesenchymal transition comparable with the ones observed in age-related macular degeneration. These findings demonstrate that PGC-1α is required to maintain the functional and phenotypic status of RPE by supporting the cells' oxidative metabolism and autophagy-mediated repression of EMT.
Mölzer C, Shankar SP, Griffith M, Islam MM, Forrester JV, Kuffová L. Activation of dendritic cells by crosslinked collagen hydrogels (artificial corneas) varies with their composition. J Tissue Eng Regen Med 2019;13(9):1528-1543.Abstract
Activated T cells are known to promote fibrosis, a major complication limiting the range of polymeric hydrogels as artificial corneal implants. As T cells are activated by dendritic cells (DC), minimally activating hydrogels would be optimal. In this study, we evaluated the ability of a series of engineered (manufactured/fabricated) and natural collagen matrices to either activate DC or conversely induce DC apoptosis in vitro. Bone marrow DC were cultured on a series of singly and doubly crosslinked hydrogels (made from recombinant human collagen III [RHCIII] or collagen mimetic peptide [CMP]) or on natural collagen-containing matrices, Matrigel and de-cellularised mouse corneal stroma. DC surface expression of major histocompatibility complex Class II and CD86 as well as apoptosis markers were examined. Natural matrices induced low levels of DC activation and maintained a "tolerogenic" phenotype. The same applied to singly crosslinked CMP-PEG gels. RHCIII gels singly crosslinked using either N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide with the coinitiator N-hydroxy succinimide (EDC-NHS) or N-cyclohexyl-N-(2-morpholinoethyl)carbodiimide metho-p-toulenesulfonate with NHS (CMC-NHS) induced varying levels of DC activation. In contrast, however, RHCIII hydrogels incorporating an additional polymeric network of 2-methacryloyloxyethyl phosphorylcholine did not activate DC but instead induced DC apoptosis, a phenomenon observed in natural matrices. This correlated with increased DC expression of leukocyte-associated immunoglobulin-like receptor-1. Despite low immunogenic potential, viable tolerogenic DC migrated into and through both natural and manufactured RHCIII gels. These data show that the immunogenic potential of RHCIII gels varies with the nature and composition of the gel. Preclinical evaluation of hydrogel immunogenic/fibrogenic potential is recommended.
Laville V, Kang JH, Cousins CC, Iglesias AI, Nagy R, Cooke Bailey JN, Igo RP, Song YE, Chasman DI, Christen WG, Kraft P, Rosner BA, Hu F, Wilson JF, Gharahkhani P, Hewitt AW, Mackey DA, Hysi PG, Hammond CJ, van Duijn CM, Haines JL, Vitart V, Fingert JH, Hauser MA, Aschard H, Wiggs JL, Khawaja AP, Macgregor S, Pasquale LR, UK Biobank, International Glaucoma Genetics Consortium NEIGHBORHOODC. Genetic correlations between diabetes and glaucoma: an analysis of continuous and dichotomous phenotypes. Am J Ophthalmol 2019;Abstract
PURPOSE: A genetic correlation is the proportion of phenotypic variance between traits that is shared on a genetic basis. Here we explore genetic correlations between diabetes- and glaucoma-related traits. DESIGN: Cross-sectional study. METHODS: We assembled genome-wide association study summary statistics from European-derived participants regarding diabetes-related traits like fasting blood sugar (FBS) and type 2 diabetes (T2D) and glaucoma-related traits (intraocular pressure (IOP), central corneal thickness (CCT), corneal hysteresis (CH), corneal resistance factor (CRF), cup-disc ratio (CDR), and primary open-angle glaucoma (POAG)). We included data from the National Eye Institute Glaucoma Human Genetics Collaboration Heritable Overall Operational Database, the UK Biobank and the International Glaucoma Genetics Consortium. We calculated genetic correlation (r) between traits using linkage disequilibrium score regression. We also calculated genetic correlations between IOP, CCT and selected diabetes-related traits based on individual level phenotype data in two Northern European population-based samples using pedigree information and Sequential Oligogenic Linkage Analysis Routines (SOLAR). RESULTS: Overall, there was little r between diabetes- and glaucoma-related traits. Specifically, we found a non-significant negative correlation between T2D and POAG (r=-0.14; p=0.16). Using SOLAR, the genetic correlations between measured IOP, CCT, FBS, fasting insulin and hemoglobin A1c, were null. In contrast, genetic correlations between IOP and POAG (r ≥0.45; p≤3.0E-04) and between CDR and POAG were high (r =0.57; p=2.8E-10). However, genetic correlations between corneal properties (CCT, CRF and CH) and POAG were low (r range: -0.18 - 0.11) and non-significant (p≥0.07). CONCLUSION: These analyses suggest there is limited genetic correlation between diabetes- and glaucoma-related traits.
Dohlman JC, Habib LA, Freitag SK. Punctal agenesis: Embryology, presentation, management modalities and outcomes. Ann Anat 2019;224:113-116.Abstract
Punctal agenesis is defined as the absence of the punctum occurring secondary to a failure of embryogenesis. This review synthesizes existing data on the embryology, anatomy, clinical presentation, symptomatology, management options and treatment outcomes of punctal agenesis. A foundational knowledge of the underlying embryologic and anatomical abnormalities is fundamental to understanding its clinical presentation and assists in choosing an appropriate management strategy. Existing outcomes data is generally favorable and suggests management with a step-wise approach can alleviate symptoms in patients across a spectrum of disease.
Smits DJ, Elze T, Wang H, Pasquale LR. Machine Learning in the Detection of the Glaucomatous Disc and Visual Field. Semin Ophthalmol 2019;:1-11.Abstract
Glaucoma is the leading cause of irreversible blindness worldwide. Early detection is of utmost importance as there is abundant evidence that early treatment prevents disease progression, preserves vision, and improves patients' long-term quality of life. The structure and function thresholds that alert to the diagnosis of glaucoma can be obtained entirely via digital means, and as such, screening is well suited to benefit from artificial intelligence and specifically machine learning. This paper reviews the concepts and current literature on the use of machine learning for detection of the glaucomatous disc and visual field.
Ponce CR, Xiao W, Schade PF, Hartmann TS, Kreiman G, Livingstone MS. Evolving Images for Visual Neurons Using a Deep Generative Network Reveals Coding Principles and Neuronal Preferences. Cell 2019;177(4):999-1009.e10.Abstract
What specific features should visual neurons encode, given the infinity of real-world images and the limited number of neurons available to represent them? We investigated neuronal selectivity in monkey inferotemporal cortex via the vast hypothesis space of a generative deep neural network, avoiding assumptions about features or semantic categories. A genetic algorithm searched this space for stimuli that maximized neuronal firing. This led to the evolution of rich synthetic images of objects with complex combinations of shapes, colors, and textures, sometimes resembling animals or familiar people, other times revealing novel patterns that did not map to any clear semantic category. These results expand our conception of the dictionary of features encoded in the cortex, and the approach can potentially reveal the internal representations of any system whose input can be captured by a generative model.
Gaiha GD, Rossin EJ, Urbach J, Landeros C, Collins DR, Nwonu C, Muzhingi I, Anahtar MN, Waring OM, Piechocka-Trocha A, Waring M, Worrall DP, Ghebremichael MS, Newman RM, Power KA, Allen TM, Chodosh J, Walker BD. Structural topology defines protective CD8 T cell epitopes in the HIV proteome. Science 2019;364(6439):480-484.Abstract
Mutationally constrained epitopes of variable pathogens represent promising targets for vaccine design but are not reliably identified by sequence conservation. In this study, we employed structure-based network analysis, which applies network theory to HIV protein structure data to quantitate the topological importance of individual amino acid residues. Mutation of residues at important network positions disproportionately impaired viral replication and occurred with high frequency in epitopes presented by protective human leukocyte antigen () class I alleles. Moreover, CD8 T cell targeting of highly networked epitopes distinguished individuals who naturally control HIV, even in the absence of protective alleles. This approach thereby provides a mechanistic basis for immune control and a means to identify CD8 T cell epitopes of topological importance for rational immunogen design, including a T cell-based HIV vaccine.
Bagdonaite-Bejarano L, Hansen RM, Fulton AB. Microperimetry in Three Inherited Retinal Disorders. Semin Ophthalmol 2019;:1-6.Abstract
Microperimetry (MP) is used to assess visual sensitivity mediated by the central retina. As such, MP performance is a candidate outcome measure for gene therapy trials. Herein, we review MP results in three inherited retinal disorders for which gene therapy trials have been initiated-choroideremia, Stargardt disease, and X-linked juvenile retinoschisis. Each of these disorders typically presents in childhood and each has distinct effects on the central retina. Our review indicates that microperimetry is feasible in each of these conditions. The MP sensitivity maps vary among conditions consistent with known effects of each of the three conditions. There is, however, within each of the three disorders considerable variability in fixation stability and in the pattern of sensitivity loss. Microperimetry is a valuable tool for monitoring functional aspects of central retina in an individual patient, especially in combination with other modalities such as OCT, autofluorescence, and acuity and thus may contribute to evaluating the efficacy of gene treatments. Variability of the MP parameters raises some cautions in application of MP as an outcome measure in treatment trials that may have small sample sizes. Nonetheless, we suspect that MP will continue to have a rightful place in future gene therapy trials.
Unzu C, Planet E, Brandenberg N, Fusil F, Cassano M, Perez-Vargas J, Friedli M, Cosset F-L, Lutolf MP, Wildhaber BE, Trono D. Pharmacological Induction of a Progenitor State for the Efficient Expansion of Primary Human Hepatocytes. Hepatology 2019;69(5):2214-2231.Abstract
The liver is an organ with strong regenerative capacity, yet primary hepatocytes have a low amplification potential in vitro, a major limitation for the cell-based therapy of liver disorders and for ex vivo biological screens. Induced pluripotent stem cells (iPSCs) may help to circumvent this obstacle but often harbor genetic and epigenetic abnormalities, limiting their potential. Here, we describe the pharmacological induction of proliferative human hepatic progenitor cells (HPCs) through a cocktail of growth factors and small molecules mimicking the signaling events involved in liver regeneration. Human HPCs from healthy donors and pediatric patients proliferated vigorously while maintaining their genomic stability and could be redifferentiated in vitro into metabolically competent cells that supported the replication of hepatitis B and delta viruses. Redifferentiation efficiency was boosted by three-dimensional culture. Finally, transcriptome analysis showed that HPCs were more closely related to mature hepatocytes than iPSC-derived hepatocyte-like cells were. Conclusion: HPC induction holds promise for a variety of applications such as ex vivo disease modeling, personalized drug testing or metabolic studies, and development of a bioartificial liver.
Morthen MK, Tellefsen S, Richards SM, Lieberman SM, Rahimi Darabad R, Kam WR, Sullivan DA. Testosterone Influence on Gene Expression in Lacrimal Glands of Mouse Models of Sjögren Syndrome. Invest Ophthalmol Vis Sci 2019;60(6):2181-2197.Abstract
Purpose: Sjögren syndrome is an autoimmune disorder that occurs almost exclusively in women and is associated with extensive inflammation in lacrimal tissue, an immune-mediated destruction and/or dysfunction of glandular epithelial cells, and a significant decrease in aqueous tear secretion. We discovered that androgens suppress the inflammation in, and enhance the function of, lacrimal glands in female mouse models (e.g., MRL/MpJ-Tnfrsf6lpr [MRL/lpr]) of Sjögren syndrome. In contrast, others have reported that androgens induce an anomalous immunopathology in lacrimal glands of nonobese diabetic/LtJ (NOD) mice. We tested our hypothesis that these hormone actions reflect unique, strain- and tissue-specific effects, which involve significant changes in the expression of immune-related glandular genes. Methods: Lacrimal glands were obtained from age-matched, adult, female MRL/lpr and NOD mice after treatment with vehicle or testosterone for up to 3 weeks. Tissues were processed for analysis of differentially expressed mRNAs using CodeLink Bioarrays and Affymetrix GeneChips. Data were analyzed with bioinformatics and statistical software. Results: Testosterone significantly influenced the expression of numerous immune-related genes, ontologies, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in lacrimal glands of MRL/lpr and NOD mice. The nature of this hormone-induced immune response was dependent upon the autoimmune strain, and was not duplicated within lacrimal tissues of nonautoimmune BALB/c mice. The majority of immune-response genes regulated by testosterone were of the inflammatory type. Conclusions: Our findings support our hypothesis and indicate a major role for the lacrimal gland microenvironment in mediating androgen effects on immune gene expression.
Kang JH, Boumenna T, Stein JD, Khawaja A, Rosner BA, Wiggs JL, Pasquale LR. Association of Statin Use and High Serum Cholesterol Levels With Risk of Primary Open-Angle Glaucoma. JAMA Ophthalmol 2019;Abstract
Importance: The use of statins (hydroxymethylglutaryl coenzyme A inhibitors) has been associated with a lower risk of primary open-angle glaucoma (POAG); however, results have been conflicting, and little is known about the association between high cholesterol levels and POAG. Objective: To assess the association of elevated cholesterol levels and statin use with incident POAG. Design, Setting, and Participants: This study used data collected biennially from participants aged 40 years or older who were free of glaucoma and reported eye examinations, within 3 population-based cohorts: the Nurses' Health Study (N = 50 710; followed up from 2000 to 2014), the Nurses' Health Study 2 (N = 62 992; 1999-2015), and the Health Professionals Follow-up Study (N = 23 080; 2000-2014). Incident cases of POAG were confirmed by medical record review. The analyses were performed in January 2019. Exposures: Biennially updated self-reported information on elevated cholesterol level status, serum cholesterol levels, and duration of statin use. Main Outcomes and Measures: Multivariable-adjusted relative risks (RRs) and 95% CIs were estimated using Cox proportional hazards regression models on pooled data, with stratification by cohort. Results: Among the 136 782 participants in the 3 cohorts (113 702 women and 23 080 men), 886 incident cases of POAG were identified. Every 20-mg/dL increase in total serum cholesterol was associated with a 7% increase in risk of POAG (RR, 1.07 [95% CI, 1.02-1.11]; P = .004). Any self-reported history of elevated cholesterol was also associated with a higher risk of POAG (RR, 1.17 [95% CI, 1.00-1.37]). A history of any statin use was associated with a 15% lower risk of POAG (RR, 0.85 [95% CI, 0.73-0.99]). Use of statins for 5 or more years vs never use of statins was associated with a 21% lower risk of POAG (RR, 0.79 [95% CI, 0.65-0.97]; P = .02 for linear trend). The association between use of statins for 5 or more years vs never use of statins and risk of POAG was more inverse in those who were older (≥65 years: RR, 0.70 [95% CI, 0.56-0.87] vs <65 years: RR, 1.05 [95% CI, 0.68-1.63]; P = .01 for interaction). Conclusions and Relevance: Among adults aged 40 years or older, higher serum cholesterol levels were associated with higher risk of POAG, while 5 or more years of statin use compared with never use of statins was associated with a lower risk of POAG.
Cheung CS, VanderVeen DK. Intraocular Lens Techniques in Pediatric Eyes with Insufficient Capsular Support: Complications and Outcomes. Semin Ophthalmol 2019;:1-10.Abstract
Intraocular lens (IOL) implantation in pediatric eyes with insufficient capsular support is challenging and there are multiple IOL options. These include placement of an IOL within the capsular bag with a capsular tension ring, a scleral-fixated posterior-chamber IOL (PCIOL) with or without capsular tension segment or ring, an intra-scleral fixated IOL, an iris-sutured PCIOL, or an anterior chamber iris-fixated IOL. We reviewed 48 articles and 1 published abstract describing the surgical techniques, complications and visual outcomes of different IOL options in the management of aphakic pediatric eyes with insufficient capsular support. The present review found that the visual acuity outcomes of various IOLs are comparable. Furthermore, each .
Shu DY, Hutcheon AEK, Zieske JD, Guo X. Epidermal Growth Factor Stimulates Transforming Growth Factor-Beta Receptor Type II Expression In Corneal Epithelial Cells. Sci Rep 2019;9(1):8079.Abstract
We previously demonstrated that inhibition of epidermal growth factor receptor (EGFR) slowed corneal epithelial migration. Here we examine the effect of EGF on transforming growth factor-beta receptor II (TGF-βRII) in a corneal wound-healing model and primary human corneal epithelial cells (pHCE). Corneal debridement wounds were made and allowed to heal ± Tyrphostin AG1478 (EGFR inhibitor), and assayed for EGFR activation and EGFR and TGF-βRII localization. Primary HCE were treated with EGF ± U0126 (MEK inhibitor) and assayed for TGF-βRII expression. EGFR activation was maximal 15 minutes after wounding and localized in the migrating epithelial cells. TGF-βRII localization was also observed in the migrating epithelium and was reduced when EGFR was blocked. When pHCE were treated with EGF for 6 hours, the cells produced enhanced levels of TGF-βRII, which was blocked by U0126. Downstream signaling pathways of MEK (p38 and ERK1/2) were then examined, and TGF-β1 and EGF were found to have differential effects on the phosphorylation of p38 and ERK1/2, with TGF-β1 upregulating p-p38 but not pERK1/2 and EGF upregulating pERK1/2 but not p-p38. Taken together, these data indicate that EGF stimulates TGF-βRII through ERK1/2 and EGFR signaling, suggesting interplay between EGF- and TGF-β-signaling pathways during corneal wound repair.