Growth cones (GCs) are structures associated with growing neurons. GC membrane expansion, which necessitates protein-lipid interactions, is critical to axonal elongation in development and in adult neuritogenesis. We present a multi-omic analysis that integrates proteomics and lipidomics data for the identification of GC pathways, cell phenotypes, and lipid-protein interactions, with an analytic platform to facilitate the visualization of these data. We combine lipidomic data from GC and adult axonal regeneration following optic nerve crush. Our results reveal significant molecular variability in GCs across developmental ages that aligns with the upregulation and downregulation of lipid metabolic processes and correlates with distinct changes in the lipid composition of GC plasmalemma. We find that these processes also define the transition into a growth-permissive state in the adult central nervous system. The insight derived from these analyses will aid in promoting adult regeneration and functional innervation in devastating neurodegenerative diseases.
: To present five cases of lower eyelid cicatricial entropion secondary to ocular cicatricial pemphigoid (OCP) successfully repaired with a conjunctival-sparing surgical technique.: The records of one surgeon (SKF) were reviewed to identify patients with lower eyelid cicatricial entropion secondary to OCP who underwent repair with a conjunctival-sparing technique between September 1, 2016 and October 18, 2017. The medical records were reviewed and extracted data included: age, gender, past medical history, current medical and OCP status, clinical examination, details of entropion repair surgery, and outcome.: Five patients (three female, two male) were included with ages ranging from 44 to 93 years. All had biopsy proven OCP, which was in remission at the time of surgery, and all were currently receiving immunomodulatory medications. All patients were symptomatic from cicatricial entropion secondary to OCP and underwent successful lower eyelid entropion repair with a conjunctival-sparing technique described herein, involving infraciliary rotation with suture fixation of the orbicularis muscle to the tarsus. Other contributing mechanisms of eyelid malposition including horizontal eyelid laxity and orbicularis oculi override were addressed simultaneously with lateral tarsal plication or orbicularis muscle debulking, resulting in 100% anatomic success and relief of symptoms with no cases of OCP reactivation, and with good durability with an average 13.9 months follow up (range 6.5-22 months).: Successful repair of lower eyelid cicatricial entropion in immunomodulated patients with OCP can be achieved without disease reactivation using a surgical technique that spares the conjunctiva and lower eyelid retractors.
The functional competence of corneal endothelial cells (CEnCs) is critical for survival of corneal allografts, but these cells are often targets of the immune response mediated by graft-attacking effector T cells. Although regulatory T cells (Tregs) have been studied for their role in regulating the host's alloimmune response towards the graft, the cytoprotective function of these cells on CEnCs has not been investigated. The aim of this study was to determine whether Tregs suppress effector T cell-mediated and inflammatory cytokine-induced CEnC death, and to elucidate the mechanism by which this cytoprotection occurs. Using 2 well-established models of corneal transplantation (low-risk and high-risk models), we show that Tregs derived from low-risk graft recipients have a superior capacity in protecting CEnCs against effector T cell-mediated and interferon-γ and tumor necrosis factor-α-induced cell death compared to Tregs derived from high-risk hosts. We further demonstrate that the cytoprotective function of Tregs derived from low-risk hosts occurs independently of direct cell-cell contact and is mediated by the immunoregulatory cytokine IL-10. Our study is the first to report that Tregs provide cytoprotection for CEnCs through secretion of IL-10, indicating potentially novel therapeutic targets for enhancing CEnC survival following corneal transplantation.
Craig JE, Han X, Qassim A, Hassall M, Cooke Bailey JN, Kinzy TG, Khawaja AP, An J, Marshall H, Gharahkhani P, Igo RP, Graham SL, Healey PR, Ong J-S, Zhou T, Siggs O, Law MH, Souzeau E, Ridge B, Hysi PG, Burdon KP, Mills RA, Landers J, Ruddle JB, Agar A, Galanopoulos A, White AJR, Willoughby CE, Andrew NH, Best S, Vincent AL, Goldberg I, Radford-Smith G, Martin NG, Montgomery GW, Vitart V, Hoehn R, Wojciechowski R, Jonas JB, Aung T, Pasquale LR, Cree AJ, Sivaprasad S, Vallabh NA, Vallabh NA, and Consortium UKBEV, Viswanathan AC, Pasutto F, Haines JL, Klaver CCW, van Duijn CM, Casson RJ, Foster PJ, Khaw PT, Hammond CJ, Mackey DA, Mitchell P, Lotery AJ, Wiggs JL, Hewitt AW, Macgregor S. Multitrait analysis of glaucoma identifies new risk loci and enables polygenic prediction of disease susceptibility and progression. Nat Genet 2020;52(2):160-166.Abstract
Glaucoma, a disease characterized by progressive optic nerve degeneration, can be prevented through timely diagnosis and treatment. We characterize optic nerve photographs of 67,040 UK Biobank participants and use a multitrait genetic model to identify risk loci for glaucoma. A glaucoma polygenic risk score (PRS) enables effective risk stratification in unselected glaucoma cases and modifies penetrance of the MYOC variant encoding p.Gln368Ter, the most common glaucoma-associated myocilin variant. In the unselected glaucoma population, individuals in the top PRS decile reach an absolute risk for glaucoma 10 years earlier than the bottom decile and are at 15-fold increased risk of developing advanced glaucoma (top 10% versus remaining 90%, odds ratio = 4.20). The PRS predicts glaucoma progression in prospectively monitored, early manifest glaucoma cases (P = 0.004) and surgical intervention in advanced disease (P = 3.6 × 10). This glaucoma PRS will facilitate the development of a personalized approach for earlier treatment of high-risk individuals, with less intensive monitoring and treatment being possible for lower-risk groups.
Adeno-associated virus (AAV) is a highly promising gene transfer vector, yet major cellular requirements for AAV entry are poorly understood. Using a genome-wide CRISPR screen for entry of evolutionarily divergent serotype AAVrh32.33, we identified GPR108, a member of the G protein-coupled receptor superfamily, as an AAV entry factor. Of greater than 20 divergent AAVs across all AAV clades tested in human cell lines, only AAV5 transduction was unaffected in the GPR108 knockout (KO). GPR108 dependency was further shown in murine and primary cells in vitro. These findings are further validated in vivo, as the Gpr108 KO mouse demonstrates 10- to 100-fold reduced expression for AAV8 and rh32.33 but not AAV5. Mechanistically, both GPR108 N- and C-terminal domains are required for transduction, and on the capsid, a VP1 unique domain that is not conserved on AAV5 can be transferred to confer GPR108 independence onto AAV2 chimeras. In vitro binding and fractionation studies indicate reduced nuclear import and cytosolic accumulation in the absence of GPR108. We thus have identified the second of two AAV entry factors that is conserved between mice and humans relevant both in vitro and in vivo, further providing a mechanistic understanding to the tropism of AAV gene therapy vectors.
PURPOSE: Cutaneous melanoma metastatic to the vitreous is very rare. This study investigated the clinical findings, treatment, and outcome of patients with metastatic cutaneous melanoma to the vitreous. Most patients received checkpoint inhibition for the treatment of systemic disease, and the significance of this was explored. DESIGN: Multicenter, retrospective cohort study. PARTICIPANTS: Fourteen eyes of 11 patients with metastatic cutaneous melanoma to the vitreous. METHODS: Clinical records, including fundus photography and ultrasound results, were reviewed retrospectively, and relevant data were recorded for each patient eye. MAIN OUTCOME MEASURES: Clinical features at presentation, ophthalmic and systemic treatments, and outcomes. RESULTS: The median age at presentation of ophthalmic disease was 66 years (range, 23-88 years), and the median follow-up from diagnosis of ophthalmic disease was 23 months. Ten of 11 patients were treated with immune checkpoint inhibition at some point in the treatment course. The median time from starting immunotherapy to ocular symptoms was 17 months (range, 4.5-38 months). Half of eyes demonstrated amelanotic vitreous debris. Five eyes demonstrated elevated intraocular pressure, and 4 eyes demonstrated a retinal detachment. Six patients showed metastatic disease in the central nervous system. Ophthalmic treatment included external beam radiation (30-40 Gy) in 6 eyes, intravitreous melphalan (10-20 μg) in 4 eyes, enucleation of 1 eye, and local observation while receiving systemic treatment in 2 eyes. Three eyes received intravitreous bevacizumab for neovascularization. The final Snellen visual acuity ranged from 20/20 to no light perception. CONCLUSIONS: The differential diagnosis of vitreous debris in the context of metastatic cutaneous melanoma includes intravitreal metastasis, and this seems to be particularly apparent during this era of treatment with checkpoint inhibition. External beam radiation, intravitreous melphalan, and systemic checkpoint inhibition can be used in the treatment of ophthalmic disease. Neovascular glaucoma and retinal detachments may occur, and most eyes show poor visual potential. Approximately one quarter of patients demonstrated ocular disease that preceded central nervous system metastasis. Patients with visual symptoms or vitreous debris in the context of metastatic cutaneous melanoma would benefit from evaluation by an ophthalmic oncologist.
The tightly structured neural retina has a unique vascular network comprised of three interconnected plexuses in the inner retina (and choroid for outer retina), which provide oxygen and nutrients to neurons to maintain normal function. Clinical and experimental evidence suggests that neuronal metabolic needs control both normal retinal vascular development and pathological aberrant vascular growth. Particularly, photoreceptors, with the highest density of mitochondria in the body, regulate retinal vascular development by modulating angiogenic and inflammatory factors. Photoreceptor metabolic dysfunction, oxidative stress, and inflammation may cause adaptive but ultimately pathological retinal vascular responses, leading to blindness. Here we focus on the factors involved in neurovascular interactions, which are potential therapeutic targets to decrease energy demand and/or to increase energy production for neovascular retinal disorders.
Importance: Among eyes with center-involved diabetic macular edema (CI-DME) and good visual acuity (VA), randomized clinical trial results showed no difference in VA loss between initial observation plus aflibercept only if VA decreased, initial focal/grid laser plus aflibercept only if VA decreased, or prompt aflibercept. Understanding the initial observation approach is relevant to patient management. Objective: To assess the DRCR Retina Network protocol-defined approach and outcomes of initial observation with aflibercept only if VA worsened. Design, Setting, and Participants: This was a post hoc secondary analyses of a randomized clinical trial of the DRCR Retina Network Protocol V that included 91 US and Canadian sites from November 2013 to September 2018. Participants were adults (n = 236) with type 1 or 2 diabetes, 1 study eye with CI-DME, and VA letter score at least 79 (Snellen equivalent, 20/25 or better) assigned to initial observation. Data were analyzed from March 2019 to November 2019. Interventions: Initial observation and follow-up with aflibercept only for VA loss of at least 10 letters from baseline at 1 visit or 5 to 9 letters at 2 consecutive visits. Follow-up occurred at 8 weeks and then every 16 weeks unless VA or optical coherence tomography central subfield thickness worsened. Main Outcomes and Measures: Whether individuals received aflibercept. Results: Among 236 eyes in 236 individuals (149 [63%] male; median age, 60 years [interquartile range, 53-67 years]) randomly assigned to initial observation, 80 (34%) were treated with aflibercept during 2 years of follow-up. At 2 years, the median VA letter score was 86.0 (interquartile range, 89.0-81.0; median Snellen equivalent, 20/20 [20/16-20/25]). Receipt of aflibercept was more likely in eyes with baseline central subfield thickness at least 300 μm (Zeiss-Stratus equivalent) vs less than 300 μm (45% vs 26%; hazard ratio [HR], 1.98 [95% CI, 1.26-3.13], continuous P = .005), moderately severe nonproliferative diabetic retinopathy (Early Treatment Diabetic Retinopathy Study retinopathy severity level 47) and above vs moderate nonproliferative diabetic retinopathy (retinopathy severity level 43) and below (51% vs 27%; HR, 2.22 [95% CI, 1.42-3.47], ordinal P < .001), and among participants whose nonstudy eye received DME treatment within 4 months of randomization vs not (52% vs 25%; HR, 2.55 [95% CI, 1.64-3.99], P < .001). Conclusions and Relevance: Most eyes managed with initial observation plus aflibercept only if VA worsened maintained good vision at 2 years and did not require aflibercept for VA loss. However, the eyes in the trial were approximately twice as likely to receive aflibercept for VA loss if they had greater baseline central subfield thickness, worse diabetic retinopathy severity level, or a nonstudy eye receiving treatment for DME. Trial Registration: ClinicalTrials.gov Identifier: NCT01909791.
, Fabian ID, Abdallah E, Abdullahi SU, Abdulqader RA, Adamou Boubacar S, Ademola-Popoola DS, Adio A, Afshar AR, Aggarwal P, Aghaji AE, Ahmad A, Akib MNR, Al Harby L, Al Ani MH, Alakbarova A, Portabella SA, Al-Badri SAF, Alcasabas APA, Al-Dahmash SA, Alejos A, Alemany-Rubio E, Alfa Bio AI, Alfonso Carreras Y, Al-Haddad C, Al-Hussaini HHY, Ali AM, Alia DB, Al-Jadiry MF, Al-Jumaly U, Alkatan HM, All-Eriksson C, Al-Mafrachi AARM, Almeida AA, Alsawidi KM, Al-Shaheen AASM, Al-Shammary EH, Amiruddin PO, Antonino R, Astbury NJ, Atalay HT, Atchaneeyasakul L-O, Atsiaya R, Attaseth T, Aung TH, Ayala S, Baizakova B, Balaguer J, Balayeva R, Balwierz W, Barranco H, Bascaran C, Beck Popovic M, Benavides R, Benmiloud S, Bennani Guebessi N, Berete RC, Berry JL, Bhaduri A, Bhat S, Biddulph SJ, Biewald EM, Bobrova N, Boehme M, Boldt HC, Bonanomi MTBC, Bornfeld N, Bouda GC, Bouguila H, Boumedane A, Brennan RC, Brichard BG, Buaboonnam J, Calderón-Sotelo P, Calle Jara DA, Camuglia JE, Cano MR, Capra M, Cassoux N, Castela G, Castillo L, Català-Mora J, Chantada GL, Chaudhry S, Chaugule SS, Chauhan A, Chawla B, Chernodrinska VS, Chiwanga FS, Chuluunbat T, Cieslik K, Cockcroft RL, Comsa C, Correa ZM, Correa Llano MG, Corson TW, Cowan-Lyn KE, Csóka M, Cui X, Da Gama IV, Dangboon W, Das A, Das S, Davanzo JM, Davidson A, De Potter P, Delgado KQ, Demirci H, Desjardins L, Diaz Coronado RY, Dimaras H, Dodgshun AJ, Donaldson C, Donato Macedo CR, Dragomir MD, Du Y, Du Bruyn M, Edison KS, Eka Sutyawan WI, El Kettani A, Elbahi AM, Elder JE, Elgalaly D, Elhaddad AM, Elhassan MAM, Elzembely MM, Essuman VA, Evina TGA, Fadoo Z, Fandiño AC, Faranoush M, Fasina O, Fernández DDPG, Fernández-Teijeiro A, Foster A, Frenkel S, Fu LD, Fuentes-Alabi SL, Gallie BL, Gandiwa M, Garcia JL, García Aldana D, Gassant PY, Geel JA, Ghassemi F, Girón AV, Gizachew Z, Goenz MA, Gold AS, Goldberg-Lavid M, Gole GA, Gomel N, Gonzalez E, Gonzalez Perez G, González-Rodríguez L, Garcia Pacheco HN, Graells J, Green L, Gregersen PA, Grigorovski NDAK, Guedenon KM, Gunasekera SD, Gündüz AK, Gupta H, Gupta S, Hadjistilianou T, Hamel P, Hamid SA, Hamzah N, Hansen ED, Harbour WJ, Hartnett EM, Hasanreisoglu M, Hassan S, Hassan S, Hederova S, Hernandez J, Hernandez LMC, Hessissen L, Hordofa DF, Huang LC, Hubbard GB, Hummlen M, Husakova K, Hussein Al-Janabi AN, Ida R, Ilic VR, Jairaj V, Jeeva I, Jenkinson H, Ji X, Jo DH, Johnson KP, Johnson WJ, Jones MM, Kabesha TAB, Kabore RL, Kaliki S, Kalinaki A, Kantar M, Kao L-Y, Kardava T, Kebudi R, Kepak T, Keren-Froim N, Khan ZJ, Khaqan HA, Khauv P, Kheir WJ, Khetan V, Khodabande A, Khotenashvili Z, Kim JW, Kim JH, Kiratli H, Kivelä TT, Klett A, Komba Palet JEK, Krivaitiene D, Kruger M, Kulvichit K, Kuntorini MW, Kyara A, Lachmann ES, Lam CPS, Lam GC, Larson SA, Latinovic S, Laurenti KD, Le BHA, Lecuona K, Leverant AA, Li C, Limbu B, Long QB, López JP, Lukamba RM, Lumbroso L, Luna-Fineman S, Lutfi D, Lysytsia L, Magrath GN, Mahajan A, Majeed AR, Maka E, Makan M, Makimbetov EK, Manda C, Martín Begue N, Mason L, Mason JO, Matende IO, Materin M, Mattosinho CCDS, Matua M, Mayet I, Mbumba FB, McKenzie JD, Medina-Sanson A, Mehrvar A, Mengesha AA, Menon V, Mercado GJVD, Mets MB, Midena E, Mishra DKC, Mndeme FG, Mohamedani AA, Mohammad MT, Moll AC, Montero MM, Morales RA, Moreira C, Mruthyunjaya P, Msina MS, Msukwa G, Mudaliar SS, Muma KI, Munier FL, Murgoi G, Murray TG, Musa KO, Mushtaq A, Mustak H, Muyen OM, Naidu G, Nair AG, Naumenko L, Ndoye Roth PA, Nency YM, Neroev V, Ngo H, Nieves RM, Nikitovic M, Nkanga ED, Nkumbe H, Nuruddin M, Nyaywa M, Obono-Obiang G, Oguego NC, Olechowski A, Oliver SCN, Osei-Bonsu P, Ossandon D, Paez-Escamilla MA, Pagarra H, Painter SL, Paintsil V, Paiva L, Pal BP, Palanivelu MS, Papyan R, Parrozzani R, Parulekar M, Pascual Morales CR, Paton KE, Pawinska-Wasikowska K, Pe'er J, Peña A, Peric S, Pham CTM, Philbert R, Plager DA, Pochop P, Polania RA, Polyakov VG, Pompe MT, Pons JJ, Prat D, Prom V, Purwanto I, Qadir AO, Qayyum S, Qian J, Rahman A, Rahman S, Rahmat J, Rajkarnikar P, Ramanjulu R, Ramasubramanian A, Ramirez-Ortiz MA, Raobela Léa, Rashid R, Reddy AM, Reich E, Renner LA, Reynders D, Ribadu D, Riheia MM, Ritter-Sovinz P, Rojanaporn D, Romero L, Roy SR, Saab RH, Saakyan S, Sabhan AH, Sagoo MS, Said AMA, Saiju R, Salas B, San Román Pacheco S, Sánchez GL, Sayalith P, Scanlan TA, Schefler AC, Schoeman J, Sedaghat A, Seregard S, Seth R, Shah AS, Shakoor SA, Sharma MK, Sherief ST, Shetye NG, Shields CL, Siddiqui SN, Sidi Cheikh S, Silva S, Singh AD, Singh N, Singh U, Singha P, Sitorus RS, Skalet AH, Soebagjo HD, Sorochynska T, Ssali G, Stacey AW, Staffieri SE, Stahl ED, Stathopoulos C, Stirn Kranjc B, Stones DK, Strahlendorf C, Suarez MEC, Sultana S, Sun X, Sundy M, Superstein R, Supriyadi E, Surukrattanaskul S, Suzuki S, Svojgr K, Sylla F, Tamamyan G, Tan D, Tandili A, Tarrillo Leiva FF, Tashvighi M, Tateshi B, Tehuteru ES, Teixeira LF, Teh KH, Theophile T, Toledano H, Trang DL, Traoré F, Trichaiyaporn S, Tuncer S, Tyau-Tyau H, Umar AB, Unal E, Uner OE, Urbak SF, Ushakova TL, Usmanov RH, Valeina S, van Hoefen Wijsard M, Varadisai A, Vasquez L, Vaughan LO, Veleva-Krasteva NV, Verma N, Victor AA, Viksnins M, Villacís Chafla EG, Vishnevskia-Dai V, Vora T, Wachtel AE, Wackernagel W, Waddell K, Wade PD, Wali AH, Wang Y-Z, Weiss A, Wilson MW, Wime ADC, Wiwatwongwana A, Wiwatwongwana D, Wolley Dod C, Wongwai P, Xiang D, Xiao Y, Yam JC, Yang H, Yanga JM, Yaqub MA, Yarovaya VA, Yarovoy AA, Ye H, Yousef YA, Yuliawati P, Zapata López AM, Zein E, Zhang C, Zhang Y, Zhao J, Zheng X, Zhilyaeva K, Zia N, Ziko OAO, Zondervan M, Bowman R. Global Retinoblastoma Presentation and Analysis by National Income Level. JAMA Oncol 2020;Abstract
Importance: Early diagnosis of retinoblastoma, the most common intraocular cancer, can save both a child's life and vision. However, anecdotal evidence suggests that many children across the world are diagnosed late. To our knowledge, the clinical presentation of retinoblastoma has never been assessed on a global scale. Objectives: To report the retinoblastoma stage at diagnosis in patients across the world during a single year, to investigate associations between clinical variables and national income level, and to investigate risk factors for advanced disease at diagnosis. Design, Setting, and Participants: A total of 278 retinoblastoma treatment centers were recruited from June 2017 through December 2018 to participate in a cross-sectional analysis of treatment-naive patients with retinoblastoma who were diagnosed in 2017. Main Outcomes and Measures: Age at presentation, proportion of familial history of retinoblastoma, and tumor stage and metastasis. Results: The cohort included 4351 new patients from 153 countries; the median age at diagnosis was 30.5 (interquartile range, 18.3-45.9) months, and 1976 patients (45.4%) were female. Most patients (n = 3685 [84.7%]) were from low- and middle-income countries (LMICs). Globally, the most common indication for referral was leukocoria (n = 2638 [62.8%]), followed by strabismus (n = 429 [10.2%]) and proptosis (n = 309 [7.4%]). Patients from high-income countries (HICs) were diagnosed at a median age of 14.1 months, with 656 of 666 (98.5%) patients having intraocular retinoblastoma and 2 (0.3%) having metastasis. Patients from low-income countries were diagnosed at a median age of 30.5 months, with 256 of 521 (49.1%) having extraocular retinoblastoma and 94 of 498 (18.9%) having metastasis. Lower national income level was associated with older presentation age, higher proportion of locally advanced disease and distant metastasis, and smaller proportion of familial history of retinoblastoma. Advanced disease at diagnosis was more common in LMICs even after adjusting for age (odds ratio for low-income countries vs upper-middle-income countries and HICs, 17.92 [95% CI, 12.94-24.80], and for lower-middle-income countries vs upper-middle-income countries and HICs, 5.74 [95% CI, 4.30-7.68]). Conclusions and Relevance: This study is estimated to have included more than half of all new retinoblastoma cases worldwide in 2017. Children from LMICs, where the main global retinoblastoma burden lies, presented at an older age with more advanced disease and demonstrated a smaller proportion of familial history of retinoblastoma, likely because many do not reach a childbearing age. Given that retinoblastoma is curable, these data are concerning and mandate intervention at national and international levels. Further studies are needed to investigate factors, other than age at presentation, that may be associated with advanced disease in LMICs.
Glaucoma is a neurodegenerative disease that leads to irreversible blindness over time. Its defining feature is the loss of retinal ganglion cells (RGCs) in the eye and their axons in the optic nerve. Increased intraocular pressure (IOP) is a major risk factor for the development of glaucoma, but is neither necessary nor sufficient for the disease and its progression; this motivates research and development of new strategies for the detection and treatment of glaucoma that focus on neuroprotection - protection of RGCs from dying. In addition, for diagnosis and treatment by reducing IOP, new approaches have been developed in recent years. This article reviews current theories of pathophysiological mechanisms underlying glaucoma and recent research - with a focus on neuroprotection and current preclinical and clinical studies to improve the diagnosis and treatment of glaucoma.
Photoreceptor loss is a leading cause of blindness, but mechanisms underlying photoreceptor degeneration are not well understood. Treatment strategies would benefit from improved understanding of gene-expression patterns directing photoreceptor development, as many genes are implicated in both development and degeneration. Neural retina leucine zipper (NRL) is critical for rod photoreceptor genesis and degeneration, with NRL mutations known to cause enhanced S-cone syndrome and retinitis pigmentosa. While murine Nrl loss has been characterized, studies of human NRL can identify important insights for human retinal development and disease. We utilized iPSC organoid models of retinal development to molecularly define developmental alterations in a human model of NRL loss. Consistent with the function of NRL in rod fate specification, human retinal organoids lacking NRL develop S-opsin dominant photoreceptor populations. We report generation of two distinct S-opsin expressing populations in NRL null retinal organoids and identify MEF2C as a candidate regulator of cone development.
Mutations in transforming growth factor-beta-induced (TGFBI) gene cause clinically distinct types of corneal dystrophies. To delineate the mechanisms driving these dystrophies, we focused on the R124C mutation in TGFBI that causes lattice corneal dystrophy type1 (LCD1) and generated novel transgenic mice harbouring a single amino acid substitution of arginine 124 with cysteine in TGFBI via ssODN-mediated base-pair substitution using CRISPR/Cas9 technology. Eighty percent of homozygous and 9.1% of heterozygous TGFBI-R124C mice developed a corneal opacity at 40 weeks of age. Hematoxylin and eosin and Masson trichrome staining showed eosinophilic deposits in subepithelial corneal stroma that stained negative for Congo-red. Although amyloid deposition was not observed in TGFBI-R124C mice, irregular amorphous deposits were clearly observed via transmission electron microscopy near the basement membrane. Interestingly, we found that the corneal deposition of TGFBI protein (TGFBIp) was significantly increased in homozygous TGFBI-R124C mice, suggesting a pathogenic role for the mutant protein accumulation. Furthermore, as observed in the LCD1 patients, corneal epithelial wound healing was significantly delayed in TGFBI-R124C mice. In conclusion, our novel mouse model of TGFBI-R124C corneal dystrophy reproduces features of the human disease. This mouse model will help delineate the pathogenic mechanisms of human corneal dystrophy.
PURPOSE: Von Hippel-Lindau (VHL) disease is a hereditary disorder that can lead to ophthalmic manifestations, including retinal capillary hemangioma (RCH). The diagnosis of RCH is often guided by wide-field fluorescein angiography. In some cases, optical coherence tomography angiography (OCT-A) serves as a non-invasive alternative to FA. Herein, we used OCT-A to examine the macular microvasculature in patients with VHL disease. SUBJECTS: Subjects were selected from patients with a diagnosis of VHL. The control group included eyes without retinal diagnosis from patients with an episode of unilateral retinal detachment or trauma and age ≤ 50 years old. METHODS: Subjects were scanned on the Optovue RTVue-XR device to acquire 3mm x 3mm OCT-A images of the superficial (SCP) and deep capillary plexus (DCP). SCP and DCP vessel density (VD) were calculated after the images were binarized. Furthermore, for subjects with RCH, each OCT-A image was divided equally into four quadrants. SCP and DCP VD of quadrants with RCH were compared to those without RCH. T-tests were performed for statistical analysis. RESULTS: 67 eyes with a history of VHL disease were included as study subjects, while 16 eyes were included as controls. Significant increases in VD were found in patients with VHL disease for both the SCP (p = 0.0441) and DCP (p = 0.0344). When comparing quadrants with associated RCH development to those without, we found no significant difference in SCP VD (p = 0.160) or DCP VD (p = 0.484). CONCLUSIONS: OCT-A can detect changes in the retinal microvasculature in the macula of patients with VHL disease. OCT-A imaging may be an additional tool for screening and early detection of patients at risk of developing ocular complications of VHL disease. Future studies should explore subtle progression on OCT-A associated with the pathogenesis and development of RCH, particularly with larger scan patterns.
Corneal fibrosis develops in response to injury, infection, postsurgical complications, or underlying systemic disease that disrupts the homeostasis of the tissue leading to irregular extracellular matrix deposition within the stroma. The mechanisms that regulate corneal scarring are focused heavily on the canonical transforming growth factor-β pathway and relevant activators, and their role in promoting myofibroblast differentiation. In this paper, we discuss the biochemical pathways involved in corneal fibrosis in the context of different injury models-epithelial debridement, superficial keratectomy, and penetrating incision. We elaborate on the interplay of the major pro-fibrotic factors involved in corneal scar development (e.g., transforming growth factor-β1, thrombospondin-1, and ανβ6), and explore a novel role for extracellular vesicles secreted by the wounded epithelium and the importance of the basement membrane.
Fuchs Endothelial Corneal Dystrophy (FECD) is an age-related genetically complex disease characterized by increased oxidative DNA damage and progressive degeneration of corneal endothelial cells (HCEnCs). FECD has a greater incidence and advanced phenotype in women, suggesting a possible role of hormones in the sex-driven differences seen in the disease pathogenesis. In this study, catechol estrogen (4-OHE), the byproduct of estrogen metabolism, induced genotoxic estrogen-DNA adducts formation, macromolecular DNA damage, and apoptotic cell death in HCEnCs; these findings were potentiated by menadione (MN)-mediated reactive oxygen species (ROS). Expression of NQO1, a key enzyme that neutralizes reactive estrogen metabolites, was downregulated in FECD, indicating HCEnC susceptibility to reactive estrogen metabolism in FECD. NQO1 deficiency in vitro exacerbated the estrogen-DNA adduct formation and loss of cell viability, which was rescued by the supplementation of N-acetylcysteine, a ROS scavenger. Notably, overexpression of NQO1 in HCEnCs treated with MN and 4-OHE quenched the ROS formation, thereby reducing the DNA damage and endothelial cell loss. This study signifies a pivotal role for NQO1 in mitigating the macromolecular oxidative DNA damage arising from the interplay between intracellular ROS and impaired endogenous estrogen metabolism in post-mitotic ocular tissue cells. A dysfunctional Nrf2-NQO1 axis in FECD renders HCEnCs susceptible to catechol estrogens and estrogen-DNA adducts formation. This novel study highlights the potential role of NQO1-mediated estrogen metabolite genotoxicity in explaining the higher incidence of FECD in females.
Nolan JG, Vestal M, Stone S, Dagi LR. "Plugged In". Orbit 2020;39(1):73-74.
Spatial patterns presented on the tongue using electro-tactile sensory substitution devices (SSDs) have been suggested to be recognized better by tracing the pattern with the tip of the tongue. We examined if the functional benefit of tracing is overcoming the poor sensitivity or low spatial resolution at the back of the tongue or alternatively compensating for limited information processing capacity by fixating on a segment of the spatial pattern at a time. Using a commercially available SSD, the BrainPort, we compared letter recognition performance in three presentation modes; tracing, static, and drawing. Stimulation intensity was either constant or increased from the tip to the back of the tongue to partially compensate for the decreasing sensitivity. Recognition was significantly better for tracing, compared to static and drawing conditions. Confusion analyses showed that letters were confused based on their characteristics presented near the tip in static and drawing conditions. The results suggest that recognition performance is limited by the poor spatial resolution at the back of the tongue, and tracing seems to be an effective strategy to overcome this. Compensating for limited information processing capacity or poor sensitivity by drawing or increasing intensity at the back, respectively, does not improve the performance.