Oxidative Stress and Its Regulation in Diabetic Retinopathy.

Diabetic retinopathy is the retinal disease associated with hyperglycemia in patients who suffer from type 1 or type 2 diabetes. It includes maculopathy, involving the central retina and characterized by ischemia and/or edema, and peripheral retinopathy that progresses to a proliferative stage with neovascularization. Approximately 10% of the global population is estimated to suffer from diabetes, and around one in 5 of these individuals have diabetic retinopathy. One of the major effects of hyperglycemia is oxidative stress, the pathological state in which elevated production of reactive oxygen species damages tissues, cells, and macromolecules. The retina is relatively prone to oxidative stress due to its high metabolic activity. This review provides a summary of the role of oxidative stress in diabetic retinopathy, including a description of the retinal cell players and the molecular mechanisms. It discusses pathological processes, including the formation and effects of advanced glycation end-products, the impact of metabolic memory, and involvements of non-coding RNA. The opportunities for the therapeutic blockade of oxidative stress in diabetic retinopathy are also considered.

Dengue Virus Infection of Human Retinal Müller Glial Cells.

Retinopathy is a recently recognized complication of dengue, affecting up to 10% of hospitalized patients. Research on the pathogenesis has focused largely on effects of dengue virus (DENV) at the blood-retinal barrier. Involvement of retinal Müller glial cells has received little attention, although this cell population contributes to the pathology of other intraocular infections. The goal of our work was to establish the susceptibility of Müller cells to infection with DENV and to identify characteristics of the cellular antiviral, inflammatory, and immunomodulatory responses to DENV infection in vitro. Primary human Müller cell isolates and the MIO-M1 human Müller cell line were infected with the laboratory-adapted Mon601 strain and DENV serotype 1 and 2 field isolates, and cell-DENV interactions were investigated by immunolabelling and quantitative real-time polymerase chain reaction. Müller cells were susceptible to DENV infection, but experiments involving primary cell isolates indicated inter-individual variation. Viral infection induced an inflammatory response (including tumour necrosis factor-α, interleukin [IL]-1ß, and IL-6) and an immunomodulatory response (including programmed death-ligand [PD-L]1 and PD-L2). The type I interferon response was muted in the Müller cell line compared to primary cell isolates. The highest infectivity and cell responses were observed in the laboratory-adapted strain, and overall, infectivity and cell responses were stronger in DENV2 strains. This work demonstrates that Müller cells mount an antiviral and immune response to DENV infection, and that this response varies across cell isolates and DENV strain. The research provides a direction for future efforts to understand the role of human retinal Müller glial cells in dengue retinopathy.

Infection of Human Retinal Pigment Epithelial Cells with Dengue Virus Strains Isolated during Outbreaks in Singapore.

Prevalence of dengue retinopathy varies across epidemics, with the disease linked to circulation of dengue virus serotype 1 (DENV-1). The retinal pigment epithelium has been implicated in the pathology. We investigated infectivity, molecular response, and barrier function of epithelial cells inoculated with DENV strains from different outbreaks in Singapore. Monolayers of human retinal pigment epithelial cells (multiple primary cell isolates and the ARPE-19 cell line) were inoculated with six DENV strains, at multiplicity of infection of 10; uninfected and recombinant strain-infected controls were included where relevant. Infectivity and cell response were assessed primarily by RT-qPCR on total cellular RNA, and barrier function was evaluated as electrical resistance across monolayers. Higher viral RNA loads were measured in human retinal pigment epithelial cells infected with DENV-1 strains from the 2005 Singapore epidemic, when retinopathy was prevalent, versus DENV-1 strains from the 2007 Singapore epidemic, when retinopathy was not observed. Type I interferon (IFN) transcripts (IFN-ß and multiple IFN-stimulated genes) were up-regulated, and impact on barrier function was more pronounced, for cells infected with DENV-1 strains from the 2005 versus the 2007 Singapore epidemics. Aside from serotype, strain of DENV may determine the potential to induce retinal pathology. Identification of molecular markers of disease-associated DENV strains may provide insights into the pathogenesis of dengue retinopathy.

Posterior segment findings by spectral-domain optical coherence tomography and clinical associations in active toxoplasmic retinochoroiditis.

Toxoplasmic retinochoroiditis is a common, potentially blinding parasitic infection. We sought to define the spectrum and frequency of signs of active toxoplasmic retinochoroiditis by spectral domain optical coherence tomography (SD-OCT), and to identify clinical associations. Ninety eyes of 90 individuals presenting consecutively to a tertiary referral uveitis service with active toxoplasmic retinochoroiditis and gradable SD-OCT scans were evaluated prospectively. SD-OCT features were collated, and associations with lesion location, primary versus recurrent episode, serological status, human immunodeficiency virus infection and best-corrected Snellen visual acuity were explored. Active toxoplasmic retinochoroiditis presented with thickened (65%) and hyperreflective (61%) retina, choroidal thickening (55%) and hyporeflectivity (61%), hyperreflective vitreous dots (80%) and deposits (36%), and posterior hyaloid thickening (35%) on SD-OCT. Most signs occurred with similar frequency across clinical groups. Retinal hyporeflectivity (17%) was significantly associated with a visual acuity of 20/200 or worse at resolution. Our observations demonstrate that active toxoplasmic retinochoroiditis has diverse SD-OCT signs and that none are universally present. Retinal hyporeflectivity-suggesting liquefactive necrosis-predicts poor visual outcome.

Ocular syphilis.

Multiple studies around the world suggest that syphilis is re-emerging. Ocular syphilis - with a wide range of presentations, most of which are subtypes of uveitis - has become an increasingly common cause of ocular inflammation over the past 20 years. Its rising incidence, diagnostic complexity, and manifestations that have only recently been characterized make ocular syphilis relevant from the public health, clinical, and scientific perspectives. We review the demographics, epidemiology, clinical features, ocular imaging findings, diagnosis, and medical management of this condition.

Optical Coherence Tomography Findings in Ocular Syphilis Involving the Posterior Segment of the Eye.

PURPOSE: To analyse posterior segment optical coherence tomography (OCT) findings in ocular syphilis. METHODS: Medical records of 54 patients presenting consecutively with syphilitic uveitis were reviewed. Vitreous, retina and choroid (one eye/patient) were assessed by spectral-domain OCT on presentation (54 eyes) and after treatment (31 eyes). Improvement in signs and associations between presenting signs and final best corrected visual acuity (BCVA) were determined by McNemar's and Fisher's exact tests. RESULTS: Early inner retinal OCT findings included hyperreflective dots (n = 49, 91%), tongue-like projections (n = 44, 81%) and large rounded spots (n = 41, 76%). Common outer retinal findings included thickening, irregularity, elevations and/or detachment of retinal pigment epithelium (n = 46, 85%), and disruption or loss of the ellipsoid zone (n = 33, 61%). Most outer retinal changes resolved with treatment (p < .05), and common presenting signs were not associated with poor final BCVA (p > .05). CONCLUSION: OCT findings have diagnostic value in ocular syphilis, but do not predict prognosis.

Zika Virus Infection of Human Iris Pigment Epithelial Cells.

During recent Zika epidemics, adults infected with Zika virus (ZIKV) have developed organ-specific inflammatory complications. The most serious Zika-associated inflammatory eye disease is uveitis, which is commonly anterior in type, affecting both eyes and responding to corticosteroid eye drops. Mechanisms of Zika-associated anterior uveitis are unknown, but ZIKV has been identified in the aqueous humor of affected individuals. The iris pigment epithelium is a target cell population in viral anterior uveitis, and it acts to maintain immune privilege within the anterior eye. Interactions between ZIKV and human iris pigment epithelial cells were investigated with infectivity assays and RNA-sequencing. Primary cell isolates were prepared from eyes of 20 cadaveric donors, and infected for 24 hours with PRVABC59 strain ZIKV or incubated uninfected as control. Cytoimmunofluorescence, RT-qPCR on total cellular RNA, and focus-forming assays of culture supernatant showed cell isolates were permissive to infection, and supported replication and release of infectious ZIKV. To explore molecular responses of cell isolates to ZIKV infection at the whole transcriptome level, RNA was sequenced on the Illumina NextSeq 500 platform, and results were aligned to the human GRCh38 genome. Multidimensional scaling showed clear separation between transcriptomes of infected and uninfected cell isolates. Differential expression analysis indicated a vigorous molecular response of the cell to ZIKV: 7,935 genes were differentially expressed between ZIKV-infected and uninfected cells (FDR < 0.05), and 99% of 613 genes that changed at least two-fold were up-regulated. Reactome and KEGG pathway and Gene Ontology enrichment analyses indicated strong activation of viral recognition and defense, in addition to biosynthesis processes. A CHAT network included 6275 molecular nodes and 24 contextual hubs in the cell response to ZIKV infection. Receptor-interacting serine/threonine kinase 1 (RIPK1) was the most significantly connected contextual hub. Correlation of gene expression with read counts assigned to the ZIKV genome identified a negative correlation between interferon signaling and viral load across isolates. This work represents the first investigation of mechanisms of Zika-associated anterior uveitis using an in vitro human cell model. The results suggest the iris pigment epithelium mounts a molecular response that limits intraocular pathology in most individuals.

Bullying, harassment and sexual discrimination among ophthalmologists in Australia and New Zealand.

BACKGROUND: Discrimination, bullying and sexual harassment (DBSH) impact the psychological well-being of doctors and contribute to poor health outcomes. The Royal Australian and New Zealand College of Ophthalmologists (RANZCO) commissioned independent surveys to evaluate DBSH among members/trainees. METHODS: Anonymous online surveys by Best Practice Australia were undertaken in 2015 and 2018. Cross-sectional analysis was prevalence of perceived DBSH, rates of reporting, intervention and resolution undertaken. Response rate was 50% (658/1319) in 2015 and 40% (557/1401) in 2018. In both surveys, 29% were female. This is representative of the distribution of the RANZCO members. RESULTS: In a 2015 survey, 37.6% of respondents experienced DBSH, with prevalence being the highest for females (62.3%; N = 104 cf males 27.7%; N = 167) and trainees (49.2%; N = 61). In 2018, 49.2% of respondents reported DBSH with rates low for all forms of DBSH (22%-29%). Sexual harassment was reported by 12% and the least discussed or reported. Respondents strategy for taking action included draw on personal support network (25-43%), official complaints to supervisors (16-22%), human resources (2%-10%) and RANZCO (0%-6%). Reasons for not taking action included fear of impact of future career options (54.1%-60.7%), fear of victimization (35.7%-50.4%) and afraid of not being believed (31.9%-52.4%). Satisfactory resolution rates were 6% to 25%. A majority of respondents (77%) were positive about RANZCO initiatives. CONCLUSIONS: DBSH is commonly reported by RANZCO members with female ophthalmologists more than two times more likely to experience any one of the four behaviours, three times more likely to experience discrimination and six times for sexual harassment. Fear of compromising personal and career progression contribute to low levels of reporting.

Expression of microRNA in human retinal pigment epithelial cells following infection with Zaire ebolavirus.

OBJECTIVE: Survivors of Ebola virus disease (EVD) are at risk of developing blinding intraocular inflammation-or uveitis-which is associated with retinal pigment epithelial (RPE) scarring and persistence of live Zaire ebolavirus (EBOV) within the eye. As part of a large research project aimed at defining the human RPE cell response to being infected with EBOV, this work focused on the microRNAs (miRNAs) associated with the infection. RESULTS: Using RNA-sequencing, we detected 13 highly induced and 2 highly repressed human miRNAs in human ARPE-19 RPE cells infected with EBOV, including hsa-miR-1307-5p, hsa-miR-29b-3p and hsa-miR-33a-5p (up-regulated), and hsa-miR-3074-3p and hsa-miR-27b-5p (down-regulated). EBOV-miR-1-5p was also found in infected RPE cells. Through computational identification of putative miRNA targets, we predicted a broad range of regulatory activities, including effects on innate and adaptive immune responses, cellular metabolism, cell cycle progression, apoptosis and autophagy. The most highly-connected molecule in the miR-target network was leucine-rich repeat kinase 2, which is involved in neuroinflammation and lysosomal processing. Our findings should stimulate new studies on the impact of miRNA changes in EBOV-infected RPE cells to further understanding of intraocular viral persistence and the pathogenesis of uveitis in EVD survivors.

Current ophthalmology practice patterns for syphilitic uveitis.

BACKGROUND: Syphilitic uveitis is re-emerging alongside the systemic infection. In July 2017, an international group of uveitis-specialised ophthalmologists formed the International Ocular Syphilis Study Group to define current practice patterns. METHODS: 103 Study Group members based in 35 countries completed a 25-item questionnaire focused on case load, clinical presentations, use and interpretation of investigations, treatment and clinical indicators of poor prognosis. RESULTS: Members managed a mean of 6.1 patients with syphilitic uveitis in clinics that averaged 707 annual cases of uveitis (0.9%); 53.2% reported increasing numbers over the past decade. Patients presented to more members (40.2%) during secondary syphilis. Uveitis was usually posterior (60.8%) or pan (22.5%); complications included optic neuropathy, macular oedema and posterior synechiae. All members diagnosed syphilitic uveitis using serological tests (simultaneous or sequential testing algorithms), and 97.0% routinely checked for HIV co-infection. Cerebrospinal fluid (CSF) analysis was ordered by 90.2% of members, and 92.7% took uveitis plus Venereal Disease Research Laboratory test (VDRL) or fluorescent treponemal antibody absorption test (FTA-ABS) to indicate neurosyphilis. Patients were commonly co-managed with infectious disease physicians, and treated with penicillin for at least 10-14 days, plus corticosteroid. Features predicting poor outcome included optic neuropathy (86.3%) and initial misdiagnosis (63.7%). Reasons for delayed diagnosis were often practitioner-related. 82.5% of members tested every patient they managed with uveitis for syphilis. CONCLUSION: This comprehensive report by an international group of uveitis-specialised ophthalmologists provides a current approach for the management of syphilitic uveitis.

Emerging infectious uveitis: Chikungunya, dengue, Zika and Ebola: A review.

Recently recognized forms of uveitis include intraocular inflammations that occur during or following one of several emerging infectious diseases: chikungunya fever, dengue, Zika virus disease and Ebola virus disease. Anterior, intermediate, posterior and pan-uveitis have been described in individuals infected with chikungunya virus. Persons who contract dengue or Zika viruses also may develop different types of uveitis in the course of the infection: maculopathy is a common manifestation of dengue eye disease, and Zika eye disease may cause hypertensive anterior uveitis or mimic a white dot syndrome. Up to one-third of Ebola survivors develop aggressive uveitis, which is frequently associated with vision loss and complicated by cataract. There are no specific anti-viral drugs for these forms of uveitis, and thus treatment is largely supportive. In this article, we summarize the systemic infectious diseases and virology, and describe the clinical presentations, outcomes and management of emerging viral forms of uveitis.

Acute infective conjunctivitis: evidence review and management advice for New Zealand practitioners.

In this review we present and discuss recent data and provide recommendations for New Zealand practitioners regarding the diagnosis and management of acute infective conjunctivitis. In particular, we discuss clinical predictors of bacterial versus viral conjunctivitis, a potential role for routine conjunctival culture, the benefits of topical antibiotic therapy for bacterial infections, delayed treatment algorithms, choice of topical antibiotic and the restriction of selected patients from work, school or early childhood care.