Publications

2022

Gnanaguru G, Mackey A, Choi EY, Arta A, Rossato FA, Gero T, Urquhart A, Scott D, D’Amore P, Ng YS. Discovery of sterically-hindered phenol compounds with potent cytoprotective activities against ox-LDL-induced retinal pigment epithelial cell death as a potential pharmacotherapy. Free Radic Biol Med. 2022;178:360–368.
Late-stage dry age-related macular degeneration (AMD) or geographic atrophy (GA) is an irreversible blinding condition characterized by degeneration of retinal pigment epithelium (RPE) and the associated photoreceptors. Clinical and genetic evidence supports a role for dysfunctional lipid processing and accumulation of harmful oxidized lipids in the pathogenesis of GA. Using an oxidized low-density lipoprotein (ox-LDL)-induced RPE death assay, we screened and identified sterically-hindered phenol compounds with potent protective activities for RPE. The phenol-containing PPARγ agonist, troglitazone, protected against ox-LDL-induced RPE cell death, whereas other more potent PPARγ agonists did not protect RPE cells. Knockdown of PPARγ did not affect the protective activity of troglitazone in RPE, confirming the protective function is not due to the thiazolidine (TZD) group of troglitazone. Prototypical hindered phenol trolox and its analogs potently protected against ox-LDL-induced RPE cell death whereas potent antioxidants without the phenol group failed to protect RPE. Hindered phenols preserved lysosomal integrity against ox-LDL-induced damage and FITC-labeled trolox was localized to the lysosomes in RPE cells. Analogs of trolox inhibited reactive oxygen species (ROS) formation induced by ox-LDL uptake in a dose-dependent fashion and were effective at sub-micromolar concentrations. Treatment with trolox analog 2,2,5,7,8-pentamethyl-6-chromanol (PMC) significantly induced the expression of the lysosomal protein NPC-1 and reduced intracellular cholesterol level upon ox-LDL uptake. Our data indicate that the lysosomal-localized hindered phenols are uniquely potent in protecting the RPE against the toxic effects of ox-LDL, and may represent a novel pharmacotherapy to preserve the vision in patients with GA.
Lužnik Marzidovšek Z, Blanco T, Sun Z, Alemi H, Ortiz G, Nakagawa H, Chauhan S, Taylor A, Jurkunas U, Yin J, Dana R. The Neuropeptide Alpha-Melanocyte-Stimulating Hormone Is Critical for Corneal Endothelial Cell Protection and Graft Survival after Transplantation. Am J Pathol. 2022;192(2):270–280.
Corneal transplantation is the most common form of tissue transplantation. The success of corneal transplantation mainly relies on the integrity of corneal endothelial cells (CEnCs), which maintain tissue transparency by pumping out excess water from the cornea. After transplantation, the rate of CEnC loss far exceeds that seen with normal aging, which can threaten sight. The underlying mechanisms are poorly understood. Alpha-melanocyte-stimulating hormone (α-MSH) is a neuropeptide that is constitutively found in the aqueous humor with both cytoprotective and immunomodulatory effects. The curent study found high expression of melanocortin 1 receptor (MC1R), the receptor for α-MSH, on CEnCs. The effect of α-MSH/MC1R signaling on endothelial function and allograft survival in vitro and in vivo was investigated using MC1R signaling-deficient mice (Mc1re/e mice with a nonfunctional MC1R). Herein, the results indicate that in addition to its well-known immunomodulatory effect, α-MSH has cytoprotective effects on CEnCs after corneal transplantation, and the loss of MC1R signaling significantly decreases long-term graft survival in vivo. In conclusion, α-MSH/MC1R signaling is critical for CEnC function and graft survival after corneal transplantation.
ABSTRACT: Following identification of limbal stem cells, efforts have been devoted to restore and/or replace these essential progenitors of the corneal epithelium. Limbal stem cell deficiency, commonly a consequence of ocular chemical injury, results in clinically compromised vision consequent to corneal conjunctivalization. The insight of Kim and Tseng provided experimental proof of the concept that even in the presence of total limbal stem cell deficiency, amnion membrane overlay grafts can promote limbal recovery as a means of ocular surface reconstruction.
Shah Y, Fliotsos M, Alaqeel A, Boland M, Zafar S, Srikumaran D, Woreta F. Use of Teleophthalmology for Evaluation of Ophthalmic Emergencies by Ophthalmology Residents in the Emergency Department. Telemed J E Health. 2022;28(6):858–864.
Background: Utilizing telemedicine is one approach to reduce the ever-increasing burden of patients on emergency departments (EDs) and consulting physicians. Utilization of telemedicine services in the ED may also benefit resident education. Materials and Methods: Ten first-year ophthalmology residents were trained to use a Topcon 3D Optical Coherence Tomography (OCT)-1 Maestro to capture OCT images and fundus photos in patients presenting to the ED with urgent ophthalmic concerns. Findings were communicated to the supervising ophthalmologist. Retrospective chart review was conducted to obtain patient characteristics and final ophthalmologist diagnosis. Residents rated ease of use, technical reliability, and educational value through a survey. Results: From December 1, 2019, to December 1, 2020, the device was used in 109 patient encounters, capturing 887 images (average 8.1 images per encounter). Patients on whom the device was used were on average 48.5 years old (±17.2, range 17-90) and 59.6% were female. The imaging device was utilized most commonly for evaluating papilledema (n = 21, 18.6%), new-onset visual acuity/visual field defects (n = 12, 10.6%), retinal detachment/tear (n = 8, 7.1%), and ophthalmic trauma workup (n = 8, 7.1%). Eight residents completed the survey and most (n = 7) agreed or strongly agreed that the device helped them diagnose patients more accurately. Technical issues such as machine malfunction, image artifacts, and problems syncing with the electronic health record and computer were noted by survey respondents. Conclusions: The most common use of teleophthalmology in the ED setting was evaluation of papilledema; the majority of residents perceived an educational benefit from this tool. Efforts should be made to address the technical challenges to increase the utility of this device.
Chinn R, Raghuram A, Curtiss M, Gehring A, De Paula AJ, Roberts T. Repeatability of the Accommodative Response Measured by the Grand Seiko Autorefractor in Children With and Without Amblyopia and Adults. Am J Ophthalmol. 2022;236:221–231.
PURPOSE: To assess test-retest repeatability of the accommodative response (AR) in children with and without amblyopia and adults using the Grand Seiko autorefractor. DESIGN: Prospective reliability assessment. METHODS: Test-retest of accommodation was obtained while participants viewed 20/150 sized letters at 33 cm using the Grand Seiko autorefractor in children 5 to <11 years with amblyopia (n=24) and without amblyopia (n=36), and adults 18 to <35 years (n=34). Bland-Altman 95% limits of agreement (LOA) and intraclass correlation coefficients (ICCs) were used to assess repeatability and reliability. The AR between the fellow and amblyopic eyes of children with amblyopia and eye 1 and eye 2 of the visually normal participants was assessed using group comparisons. RESULTS: The 95% LOA of the AR was greatest in the amblyopic eyes (-1.25 diopters [D], 1.62 D) of children with amblyopia. The 95% LOA were similar between the fellow eyes (-0.88 D, 0.74 D) of children with amblyopia and both eyes of the children without amblyopia (eye 1: -0.68 D, 0.71 D; eye 2: -0.59 D, 0.70 D) and the adults (eye 1: 95% LOA = -0.49 D, 0.45 D; eye 2: LOA = -0.66 D, 0.67 D). ICCs revealed the Grand Seiko autorefractor as a reliable instrument for measuring AR. CONCLUSIONS: The Grand Seiko autorefractor was more repeatable and reliable when measuring the AR in children and adults without amblyopia than in the amblyopic eye in children with amblyopia. It is recommended that multiple measures of the AR be obtained in amblyopic eyes to improve the precision of measures.
Halawa O, Kolli A, Oh G, Mitchell W, Glynn R, Kim DH, Friedman D, Zebardast N. Racial and Socioeconomic Differences in Eye Care Utilization among Medicare Beneficiaries with Glaucoma. Ophthalmology. 2022;129(4):397–405.
PURPOSE: Evaluate differences in eye care utilization among patients with glaucoma by race and socioeconomic status (SES). DESIGN: Retrospective cohort study. PARTICIPANTS: Representative 5% sample of Medicare beneficiaries aged > 65 years with continuous part A/B enrollment between January 1, 2014, and July 1, 2014, at least 1 diagnosis code for glaucoma within that period, and a glaucoma diagnosis in the Chronic Conditions Warehouse before January 1, 2014. METHODS: The following race/ethnicity categories were defined in our cohort: non-Hispanic White, Black/African American, Hispanic, and Asian/Pacific Islander. Low SES was defined as having 2 or more enrollment-based low-income indicators (dual eligibility for Medicare/Medicaid, Part D limited income subsidies, and eligibility for Part A and B State buy-in). Negative binomial regression analyses were carried out to compare relative rate ratios (RRs) of eye care utilization among racial groups stratified by low and non-low SES. MAIN OUTCOME MEASURES: Measured from July 1, 2014, to December 31, 2016: eye examinations and eye care-related office visits; eye care-related inpatient and emergency department (ED) encounters; eye care-related nursing home and home-visit encounters; visual field and retinal nerve fiber OCT tests; glaucoma lasers and surgeries. RESULTS: Among 78 526 participants with glaucoma, mean age was 79.1 years (standard deviation, 7.9 years), 60.9% were female, 78.4% were non-Hispanic White, and 13.8% met enrollment-based criteria for low-SES. Compared with White beneficiaries, Blacks had lower counts of outpatient visits (RR, 0.92; 95% confidence interval [CI], 0.90-0.93), visual field (VF) tests (RR, 0.92; 95% CI, 0.90-0.94), but more inpatient/ED encounters (RR, 2.42; 95% CI, 1.55-3.78) and surgeries (RR, 1.14; 95% CI, 1.03-1.27). Hispanics had fewer outpatient visits (RR, 0.97; 95% CI, 0.95-0.98) and retinal nerve fiber layer (RNFL) OCT tests (RR, 0.89; 95% CI, 0.86-0.93), but more inpatient/ED encounters (RR, 2.32; 95% CI, 1.18-4.57) and selective laser trabeculoplasty (SLT) (RR, 1.25; 95% CI, 1.11-1.42) versus non-Hispanic Whites. In the non-low SES group, Black versus White disparities persisted in outpatient visits (RR, 0.93; 95% CI, 0.92-0.95), VF (RR, 0.96; 95% CI, 0.94-0.98), RNFL OCT (RR, 0.81; 95% CI, 0.78-0.83), and inpatient/ED encounters (RR, 2.57; 95% CI, 1.55-4.26). CONCLUSIONS: Disparities were found in eye care utilization among Black and Hispanic patients with glaucoma. These differences persisted among Blacks after stratification by SES, suggesting that systemic racism may be an independent driver in this population.