Emmanuel Chang

Essential Role for c-Jun N-Terminal Kinase 2 in Corneal Epithelial Response to Desiccating Stress

OBJECTIVEnTo investigate the protective effects of c-Jun N-terminal kinase (JNK)-1 and -2 gene knockout (KO) on the corneal epithelial response to desiccating stress.nnnMETHODSnThe C57BL/6, JNK1KO, and JNK2KO mice were subjected to desiccating stress (DS) for 5 days. The effects of DS on the corneal epithelium were evaluated by measuring corneal smoothness and permeability. Expression of matrix metalloproteinases (MMP)-1, MMP-9, and cornified envelope protein precursors (small proline-rich protein [SPRR]-1a, SPRR-2a, and involucrin) in the corneal epithelia was evaluated by immunostaining and real-time polymerase chain reaction. Collagenase and gelatinase activity in corneal sections as measured with in situ fluorescent assays.nnnRESULTSnThe JNK2KO mice had smoother corneal surfaces and less corneal barrier disruption in response to DS than JNK1KO mice and C57BL/6 wild-type control mice. The DS increased levels of MMP-1, MMP-9, SPRR-1a, SPRR-2a, involucrin immunoreactivity, and mRNA transcripts in the corneal epithelium of JNK1KO and C57BL/6 mice, but not in JNK2KO mice. Knockout of JNK2 prevented DS-induced increase in gelatinase and collagenase activity in the cornea.nnnCONCLUSIONnThe JNK2 protein appears to have an essential role in desiccation-induced corneal epithelial disease by stimulating production of MMP-1, MMP-9, and cornified envelope precursors. Clinical Relevance The JNK2 protein could be a novel therapeutic target in dry eye disease.

Biodegradable PLGA-Based Drug Delivery Systems for Modulating Ocular Surface Disease under Experimental Murine Dry Eye.

OBJECTIVEnContinuous drug delivery to the ocular surface remains difficult due to the rapid tear clearance of topically applied agents. The purpose of this study was to evaluate biodegradable and biocompatible drug delivery systems on the ocular surface using poly-lactic-co-glycolic acid (PLGA) based polymers.nnnMETHODSnFluorescein-labeled albumin and doxycycline were individually encapsulated into a PLGA-based matrix using a water-oil-water double emulsion method. The drug elution rates for various microspheres were evaluated spectrofluorometrically. Particle size was measured using image analysis software. Subconjunctival injections of PLGA microspheres were used to evaluate safety and inflammatory response to the polymer in the murine model. Efficacy of the drug delivery system was evaluated by a single subconjunctival injection of PLGA-doxycycline (a broad metalloproteinase inhibitor) prior to induction of desiccating stress (DS) model in C57BL/6 mice for 5 days.nnnRESULTSnPLGA-based microspheres successfully elute encapsulated drugs of interest continuously over controlled periods of time. Mean PLGA-based microparticle diameter was 4.6 μm±1.54 μm. Drug elution rates and delivery times were easily modifiable by altering polymers and synthesis parameters. In vitro studies demonstrate successful continuous elution of encapsulated drugs for at least 2 weeks. In vivo testing of PLGA-doxycycline was efficacious in preventing DS-induced corneal barrier disruption with desiccating stress, similarly to topically applied doxycycline.nnnCONCLUSIONSnPLGA-based drug delivery systems are safe and non-inflammatory. They can be successfully used to treat ocular surface and corneal diseases by continuously delivering biopharmaceuticals of interest.

Multimodal Imaging Of West Nile Virus Chorioretinitis

Purpose: To report the results of multimodal imaging of West Nile virus chorioretinitis. Methods: Three patients with West Nile virus chorioretinitis were evaluated by color fundus photography, fluorescein angiography, enhanced depth optical coherence tomography, indocyanine green angiography, and fundus autofluorescence. Results: Imaging results demonstrate outer retinal and retinal pigment epithelial involvement with inner retinal sparing. Conclusion: Multiple fundus imaging modalities used during the diagnosis of West Nile chorioretinitis are consistent with outer retinal and pigment epithelial changes, suggesting outer retina and retinal pigment epithelium as the primary sites of ocular involvement.

Improved Diagnosis of Inherited Retinal Dystrophies by High-Fidelity PCR of ORF15 followed by Next-Generation Sequencing

Retinitis pigmentosa (RP) is the most common form of retinal dystrophy. The disease is characterized by the progressive degeneration of photoreceptors, ultimately leading to blindness. The exon ORF15 of RPxa0GTPase regulator (RPGR) is a mutation hot spot for X-linked RP and one form of cone dystrophy. However, accurate molecular testing of ORF15 is challenging because of a large segment of highlyxa0repetitive purine-rich sequence in this exon. ORF15 performs poorly in next-generationxa0sequencing-based panels or whole exome sequencing analysis, whereas Sanger sequencing of ORF15 requires special reagents and PCR conditions with multiple pairs of overlapping primers that often do not provide a clean sequence. Because of these technical difficulties, molecular analysis of ORF15 is performed mostly in research laboratories without validation for clinical application. Herein, we report the development of a single step of high-fidelity PCR followed by next-generation sequencing for accurate mutation detection, which is easily integrated into routine clinical practice. Our approach has improved coverage depth of ORF15 with the ability to detect single-nucleotide variants and deletions/duplications. Using this method, we were able to identify ORF15 pathogenic variants in approximately 31% of undiagnosed RP patients. Our results underline the clinical importance of complete and accurate sequence analysis of ORF15 for patients with retinal dystrophies.

The phenotypic variability of HK1 -associated retinal dystrophy

Inherited retinal dystrophies (IRDs) are a clinically and genetically heterogeneous group of Mendelian disorders primarily affecting photoreceptor cells. The same IRD-causing variant may lead to different retinal symptoms, demonstrating pleiotropic phenotype traits influenced by both underlying genetic and environmental factors. In the present study, we identified four unrelated IRD families with the HK1 p.E851K variant, which was previously reported to cause autosomal dominant retinitis pigmentosa (RP), and described their detailed clinical phenotypes. Interestingly, we found that in addition to RP, this particular variant can also cause dominant macular dystrophy and cone-rod dystrophy, which primarily affect cone photoreceptors instead of rods. Our results identified pleiotropic effects for an IRD-causing variant and provide more insights into the involvement of a hexokinase in retinal pathogenesis.

Transmission of West Nile Virus Through a Hematopoietic Stem Cell Transplant

1Section of Pediatric Critical Care, Department of Pediatrics, Departments of 2Pediatric Neurology, 5Ophthalmology, and 6Pediatric Infectious Diseases, and 7Section of Hematology-Oncology, Department of Pediatrics, Texas Children’s Hospital, Baylor College of Medicine, Houston, Texas; 3Retina and Vitreous of Texas, Houston, Texas; and 4Department of Ophthalmology, Baylor College of Medicine, Houston, Texas

Immediate Sequential Bilateral Pediatric Vitreoretinal Surgery. An International Multicenter Study

PURPOSEnTo determine the feasibility and safety of bilateral simultaneous vitreoretinal surgery in pediatric patients.nnnDESIGNnInternational, multicenter, interventional, retrospective case series.nnnPARTICIPANTSnPatients 17 years of age or younger from 24 centers worldwide who underwent immediate sequential bilateral vitreoretinal surgery (ISBVS)-defined as vitrectomy, scleral buckle, or lensectomy using the vitreous cutter-performed in both eyes sequentially during the same anesthesia session.nnnMETHODSnClinical history, surgical details and indications, time under anesthesia, and intraoperative and postoperative ophthalmic and systemic adverse events were reviewed.nnnMAIN OUTCOME MEASURESnOcular and systemic adverse events.nnnRESULTSnA total of 344 surgeries from 172 ISBVS procedures in 167 patients were included in the study. The mean age of the cohort was 1.3±2.6 years. Nonexclusive indications for ISBVS were rapidly progressive disease (74.6%), systemic morbidity placing the child at high anesthesia risk (76.0%), and residence remote from surgery location (30.2%). The most common diagnoses were retinopathy of prematurity (ROP; 72.7% [P < 0.01]; stage 3, 4.8%; stage 4A, 44.4%; stage 4B, 22.4%; stage 5, 26.4%), familial exudative vitreoretinopathy (7.0%), abusive head trauma (4.1%), persistent fetal vasculature (3.5%), congenital cataract (1.7%), posterior capsular opacification (1.7%), rhegmatogenous retinal detachment (1.7%), congenital X-linked retinoschisis (1.2%), Norrie disease (2.3%), and viral retinitis (1.2%). Mean surgical time was 143±59 minutes for both eyes. Higher ROP stage correlated with longer surgical time (Pxa0= 0.02). There were no reported intraoperative ocular complications. During the immediate postoperative period, 2 eyes from different patients demonstrated unilateral vitreous hemorrhage (0.6%). No cases of endophthalmitis, choroidal hemorrhage, or hypotony occurred. Mean total anesthesia time was 203±87 minutes. There were no cases of anesthesia-related death, malignant hyperthermia, anaphylaxis, or cardiac event. There was 1 case of reintubation (0.6%) and 1 case of prolonged oxygen desaturation (0.6%). Mean follow-up after surgery was 103 weeks, and anatomic success and globe salvage rates were 89.8% and 98.0%, respectively.nnnCONCLUSIONSnThis study found ISBVS to be a feasible and safe treatment paradigm for pediatric patients with bilateral vitreoretinal pathologic features when repeated general anesthesia is undesirable or impractical.

Understanding the evolving phenotype of vascular complications in telomere biology disorders

Vascular complications such as bleeding due to gastrointestinal telangiectatic anomalies, pulmonary arteriovenous malformations, hepatopulmonary syndrome, and retinal vessel abnormalities are being reported in patients with telomere biology disorders (TBDs) more frequently than previously described. The international clinical care consortium of telomere-associated ailments and family support group Dyskeratosis Congenita Outreach, Inc. held a workshop on vascular abnormalities in the TBDs at the National Cancer Institute in October 2017. Clinicians and basic scientists reviewed current data on vascular complications, hypotheses for the underlying biology and developed new collaborations to address the etiology and clinical management of vascular complications in TBDs.

Sequential traumatic corneal open globe rupture in a patient with osteogenesis imperfecta type I

Purpose To report a case of sequential open globe rupture in a young patient with osteogenesis imperfecta type I following minor accidental blunt injury. This represented the patients sole clinical manifestation of connective tissue disease, leading to a diagnosis of osteogenesis imperfecta type I at the age of 12 years old. Observations A 12-year-old male presented with right eye pain following accidental blunt trauma at school while wearing protective lenses. One year ago, he required surgical repair of a left open globe following blunt trauma during a middle school basketball game. His exam was significant for a full-thickness corneal laceration, necessitating open globe repair of his right eye, which was remarkably difficult given the poor tissue constitution of the cornea and sclera. He was referred to a genetics specialist, where he was found to have a pathogenic heterozygous splice site variant in the COL1A1 gene, consistent with osteogenesis imperfecta type I. Conclusions and importance Connective tissue disease should be considered in any case of open globe rupture following minor trauma, even in the absence of other clinical manifestations of the disease. The surgical management of these patients is particularly challenging due to the fragility of the connective tissue. Early diagnosis of connective tissue disease is important to preserve visual acuity and prevent further damage to the eyes.

Retinal Artery Occlusions in Healthy Children

Purpose: To describe a series of retinal arterial occlusions in healthy children. Methods: Chart review from multiple US and international institutions. Results: Five episodes affecting otherwise healthy children aged 5 to 14 are described. With the exception of migraine history in 1 individual and a novel heterozygous mutation of uncertain significance in 1 patient without clinical hyper-homocysteinemia in the methylenetetrahydrofolate reductase gene, no risk factors or systemic pathology contributing to the event were identified. Conclusion: We report a series of unilateral retinal artery occlusions in otherwise healthy children. This devastating ocular disease typically elicits an extensive ophthalmologic, radiologic, hematologic, and cardiologic evaluation, which is often unrevealing in this population. There are no evidence-based guidelines to guide the extent of diagnostic evaluation or management. Sequential bilateral artery occlusions have never been reported in otherwise healthy children.