Microglia preserve visual function loss in the aging retina by supporting retinal pigment epithelial health.

BACKGROUND: Increased age is a risk factor for the development and progression of retinal diseases including age-related macular degeneration (AMD). Understanding the changes that occur in the eye due to aging is important in enhancing our understanding of AMD pathogenesis and the development of novel AMD therapies. Microglia, the resident brain and retinal immune cells are associated with both maintaining homeostasis and protection of neurons and loss of microglia homeostasis could be a significant player in age related neurodegeneration. One important characteristic of retinal aging is the migration of microglia from the inner to outer retina where they reside in the subretinal space (SRS) in contact with the retinal pigment epithelial (RPE) cells. The role of aged subretinal microglia is unknown. Here, we depleted microglia in aged C57/BL6 mice fed for 6 weeks with a chow containing PLX5622, a small molecule inhibitor of colony-stimulating factor-1 receptor (Csf1r) required for microglial survival. RESULTS: The subretinal P2RY12 + microglia in aged mice displayed a highly amoeboid and activated morphology and were filled with autofluorescence droplets reminiscent of lipofuscin. TEM indicates that subretinal microglia actively phagocytize shed photoreceptor outer segments, one of the main functions of retinal pigmented epithelial cells. PLX5622 treatment depleted up to 90% of the retinal microglia and was associated with significant loss in visual function. Mice on the microglia depletion diet showed reduced contrast sensitivity and significantly lower electroretinogram for the c-wave, a measurement of RPE functionality, compared to age-matched controls. The loss of c-wave coincided with a loss of RPE cells and increased RPE swelling in the absence of microglia. CONCLUSIONS: We conclude that microglia preserve visual function in aged mice and support RPE cell function, by phagocytosing shed photoreceptor outer segments and lipids, therefore compensating for the known age-related decline of RPE phagocytosis.

Incidence and changing patterns of uveitis in Central Tokyo.

PURPOSE: The patterns of uveitis in Tokyo have recently changed due to advances in examination tools. We aimed to investigate the changes in the patterns of uveitis between 2004-2015 and 2016-2018. METHODS: We retrospectively reviewed the data of 732 patients who visited the Uveitis Clinic at the University of Tokyo Hospital between January 2016 and December 2018. Background characteristics, laboratory results, and imaging findings were analysed. We compared the incidences of uveitis in 2016-2018 and 2004-2015 to identify changes in the patterns. RESULTS: The most frequent diagnoses were sarcoidosis (8.9%), herpetic iridocyclitis (6.7%), intraocular lymphoma (5.5%), Vogt-Koyanagi-Harada disease (4.8%), unclassified acute anterior uveitis (4.6%), Behçet's disease (4.5%), bacterial endophthalmitis (2.9%), and Posner-Schlossman syndrome (2.6%). Suspected sarcoidosis (20.9%) was the most common cause of unclassified uveitis. The incidence of intraocular lymphoma was significantly higher in 2016-2018 than in 2004-2015. Between 2004 and 2018, herpetic iridocyclitis, bacterial endophthalmitis, and juvenile chronic iridocyclitis exhibited an increasing trend, and the incidences of Posner-Schlossman syndrome, unclassified acute anterior uveitis, Behçet's disease, and Vogt-Koyanagi-Harada disease exhibited a decreasing trend. CONCLUSION: The changing patterns of uveitis were characterised by increases in the incidence of intraocular lymphoma. This may be attributed to recent advances in examination tools, the changes in the referred patient population, and the aging Japanese population.

Clinical features of uveitis in elderly patients in central Tokyo (2013-2018).

PURPOSE: To clarify the clinical features of uveitis in elderly patients in central Tokyo. METHODS: We retrospectively identified 1424 patients with uveitis who visited the Uveitis Clinic of the University of Tokyo Hospital between January 2013 and December 2018. The patients were categorized into two groups based on their ages at the time of disease onset: patients aged 65 years or older were included in Group A, whereas those younger than 65 years were included in Group B. The etiological classification of uveitis and its causes were investigated for each group. RESULTS: Group A presented significantly higher rates of infectious uveitis (35.5% vs. 17.8%, p < 0.0001) and masquerade syndromes (17.9% vs. 5.0%, p < 0.0001) than Group B. Furthermore, Group A had significantly higher rates of sarcoidosis (23.1% vs. 9.3%, p < 0.0001), intraocular lymphoma (16.6% vs. 4.6%, p < 0.0001), cytomegalovirus iritis (11.0% vs. 5.6%, p = 0.0043), and cytomegalovirus retinitis (5.2% vs. 1.5%, p = 0.0020) than Group B. CONCLUSION: Our results demonstrate a clear difference in the causative diseases of uveitis between elderly and non-elderly patients. These findings may support ophthalmologists in their diagnostic process for elderly patients with uveitis.

Comparison of visual field defect progression in secondary Glaucoma due to anterior uveitis caused by three types of herpes viruses.

PURPOSE: To clarify the prevalence of secondary glaucoma (SG) and its speed of progression in patients with herpes simplex virus (HSV)-anterior uveitis (AU), varicella zoster virus (VZV)-AU, and cytomegalovirus (CMV)-AU. METHODS: In total, 170 patients with herpetic AU were enrolled in this retrospective observational case series. Patients with visual field (VF) defects and glaucomatous disc abnormalities were diagnosed with SG. Moreover, the speed of SG progression was defined as decreasing mean deviation (MD) values per year. SG prevalence and annual MD-value decrease were compared among the three types of herpetic AU. RESULTS: SG prevalence was 16%, 9%, and 72% in patients with HSV-AU, VZV-AU, and CMV-AU, respectively. Patients with CMV-AU had the highest SG prevalence (odds ratio = 3.15; 95% confidence interval = 1.15-8.65; P < 0.05). Furthermore, the annual MD-value change was significantly higher in SG caused by CMV-AU than in that caused by HSV/VZV-AU (-2.6 ± 2.4 dB/year and -0.45 ± 0.54 dB/year, respectively; P < 0.05). CONCLUSIONS: Our results demonstrated that patients with CMV-AU may have a higher risk and faster speed of progression of SG than patients with HSV/VZV-AU. Therefore, clinicians should monitor glaucoma onset and VF-defect progression in patients with CMV-AU.

Epidemiology of uveitis (2013-2015) and changes in the patterns of uveitis (2004-2015) in the central Tokyo area: a retrospective study.

BACKGROUND: The distribution of uveitis varies with genetic, ethnic, geographic, environmental, and lifestyle factors. Epidemiological information about the patterns of uveitis is useful when an ophthalmologist considers the diagnosis of uveitis. Therefore, it is important to identify the causes of uveitis over the years in different regions. The purposes of this study were to characterize the uveitis patients who first arrived at the University of Tokyo Hospital in 2013-2015, and to analyze the changes in the patterns of uveitis from 2004 to 2012 to 2013-2015. METHODS: We retrospectively identified 750 newly arrived patients with uveitis who visited the Uveitis Clinic in the University of Tokyo Hospital between January 2013 and December 2015, using clinical records. We extracted data on patient age, sex, diagnosis, anatomic location of inflammation, laboratory test results of blood and urine, and chest X-ray and fluorescein fundus angiography findings for each patient. In addition, we compared these data with those from 2004 to 2012 to analyze the changes in the patterns of uveitis. RESULTS: A definite diagnosis was established in 445 patients (59.3%). The most common diagnoses were herpetic iridocyclitis (7.5%), sarcoidosis (6.1%), Behçet's disease (4.4%), Vogt-Koyanagi-Harada disease (4.1%), and intraocular lymphoma (4.1%). The most frequent unclassified type of uveitis was suspected sarcoidosis (22.3%). Analysis of the changes in the patterns of uveitis in the central Tokyo area from 2004 to 2012 to 2013-2015 revealed notable increasing trends of herpetic iridocyclitis and intraocular lymphoma, and increasing trends of bacterial endophthalmitis, fungal endophthalmitis, and juvenile chronic iridocyclitis. In contrast, the frequency of sarcoidosis, Behçet's disease, and Vogt-Koyanagi-Harada disease decreased. CONCLUSIONS: The patterns of uveitis changed considerably from 2004 to 2012 to 2013-2015. Continuous investigations about the epidemiology of uveitis are needed to diagnose uveitis more accurately.

A limbal stem cell deficiency murine model with residual limbal stem cells.

Bilateral limbal stem cell deficiency (LSCD) is a significant cause of corneal blindness and is more difficult to treat, as compared with unilateral LSCD because no source of autologous limbal stem cells (LSCs) remains in these patients. Thus, bilateral patients could be candidates for treatment with allogeneic LSC transplants that require long-term systemic immunosuppression therapy. Thus, if possible, for the correct candidates, using autologous LSCs could be a preferred treatment. Recent in vivo laser confocal microscopic examination of the ocular surface in situ , combined with impression cytology, has indicated that some patients diagnosed with a complete bilateral LSCD possess residual LSCs. However, it remains unknown whether these residual LSCs still have stem cell potential due to the lack of animal models that mimic this pathology. The goal of the current study is to make a complete LSCD model that possesses evidence of residual LSCs. We induced complete LSCD in mice using two methods: (1) removed the corneal epithelium and the epithelial basement membrane using a rotating burr, and (2) removed the corneal epithelium using 20% ethanol but retained an intact epithelial basement membrane. A complete LSCD was defined by a lack of CK12-positive corneal epithelial cells and the presence of infiltrating CK19-positive conjunctival epithelial cells. Corneas were examined for wound closure, corneal opacity, LSC exhaustion, and inflammation. We observed that complete LSCD mice without an intact epithelial basement membrane resulted in few residual LSCs. By contrast, complete LSCD mice that retained the epithelial basement membrane were accompanied by a reduced inflammatory response plus a significant number of residual LSCs. This model will allow future studies to determine the function of residual LSCs in complete LSCD.

Retinal microglia exacerbate uveitis by functioning as local antigen-presenting cells.

Autoimmune uveitis is a major cause of blindness in the working-age population of developed countries. Experimental autoimmune uveitis (EAU) depends on activation of interphotoreceptor retinoid-binding protein (IRBP) specific CD4 + effector T cells that migrate systemically and infiltrate into the retina. Following systemic induction of retinal antigen-specific T cells, the development of EAU can be broken down into three phases: early phase when inflammatory cells begin to infiltrate the retina, amplification phase, and peak phase. Although studied extensively, the function of local antigen-presenting cells (APCs) within the retina remains unclear. Two potential types of APCs are present during uveitis, resident microglia and infiltrating CD11c + dendritic cells (DCs). MHC class II (MHC II) is expressed within the retina on both CD11c + DCs and microglia during the amplification phase of EAU. Therefore, we used microglia specific (P2RY12 and TMEM119) and CD11c + DC specific MHC II knockout mice to study the function of APCs within the retina using the conventional and adoptive transfer methods of inducing EAU. Microglia were essential during all phases of EAU development: the early phase when microglia were MHC Il negative, and amplification and peak phases when microglia were MHC II positive. Unexpectedly, retinal infiltrating MHC Il + CD11c + DCs were present within the retina but their antigen-presenting function was not required for all phases of uveitis. Our data indicate microglia are the critical APCs within the retina and an important therapeutic target that can prevent and/or diminish uveitis even in the presence of circulating IRBP-specific CD4 + effector T cells.

Anterior Uveitis Associated with Human Herpesvirus 7 Infection Diagnosed by Multiplex Polymerase Chain Reaction Assay: A Case Report.

BACKGROUND: Herpetic anterior uveitis (AU) is usually caused by the herpes simplex virus, varicella-zoster virus, and cytomegalovirus. Herein, we report a case of herpetic AU associated with human herpesvirus 7 (HHV-7) infection. STUDY DESIGN: A case report. CASE PRESENTATION: A 49-year-old female patient presented with complaints of blurred vision and hyperemia in the right eye. Slit-lamp examination revealed bilateral fine and a few small white keratic precipitates (KPs), Descemet membrane folds in the right eye, and severe and mild cellular infiltration in the anterior chamber of the right and left eye, respectively. HHV-7 viral DNA was detected by a polymerase chain reaction assay of an aqueous humor sample. The AU improved significantly with topical steroids. CONCLUSION: We report a rare case of herpetic AU characterized by fine and small white KPs in which only HHV-7 DNA was detected in the aqueous humor.

Sustained Vision Recovery by OSK Gene Therapy in a Mouse Model of Glaucoma.

Glaucoma, a chronic neurodegenerative disease, is a leading cause of age-related blindness worldwide and characterized by the progressive loss of retinal ganglion cells (RGCs) and their axons. Previously, we developed a novel epigenetic rejuvenation therapy, based on the expression of the three transcription factors Oct4, Sox2, and Klf4 (OSK), which safely rejuvenates RGCs without altering cell identity in glaucomatous and old mice after 1 month of treatment. In the current year-long study, mice with continuous or cyclic OSK expression induced after glaucoma-induced vision damage had occurred were tracked for efficacy, duration, and safety. Surprisingly, only 2 months of OSK fully restored impaired vision, with a restoration of vision for 11 months with prolonged expression. In RGCs, transcription from the doxycycline (DOX)-inducible Tet-On AAV system, returned to baseline 4 weeks after DOX withdrawal. Significant vision improvements remained for 1 month post switching off OSK, after which the vision benefit gradually diminished but remained better than baseline. Notably, no adverse effects on retinal structure or body weight were observed in glaucomatous mice with OSK continuously expressed for 21 months providing compelling evidence of efficacy and safety. This work highlights the tremendous therapeutic potential of rejuvenating gene therapies using OSK, not only for glaucoma but also for other ocular and systemic injuries and age-related diseases.

Human U90926 orthologous long non-coding RNA as a novel biomarker for visual prognosis in herpes simplex virus type-1 induced acute retinal necrosis.

Acute retinal necrosis (ARN) is a form of infectious uveitis caused by alpha herpesviruses, including herpes simplex virus type 1 (HSV-1). We previously found that the long non-coding RNA (lncRNA) U90926 is upregulated in murine retinal photoreceptor cells following HSV-1 infection, leading to host cell death. However, to date, an orthologous transcript has not been identified in humans. We investigated U90926 orthologous transcript in humans and examined its utility as a prognostic marker for visual acuity in patients with ARN. We identified two human orthologous transcripts (1955 and 592 bases) of lncRNA U90926. The amount of the longer human U90926 transcript was approximately 30- and 40-fold higher in the vitreous fluid of patients with ARN than in those with sarcoidosis and intraocular lymphoma, respectively. Furthermore, the expression of the longer human U90926 transcript in the vitreous fluid was highly correlated with the final best-corrected logarithm of the minimum angle of resolution visual acuity in patients with ARN (r = 0.7671, p = 0.0079). This suggests higher expression of the longer human U90926 transcript in the vitreous fluid results in worse visual prognosis; therefore, expression of the longer human U90926 transcript is a potential negative prognostic marker for visual acuity in patients with ARN.

Clinical Features and Visual Outcome of Uveitis in Japanese Patients Younger than 18 Years.

Purpose: To investigate the clinical features and visual outcome of young Japanese patients with uveitis.Methods: Patients younger than 18 years who presented with uveitis at the University of Tokyo Hospital between 2000 and 2018 were retrospectively reviewed.Results: The study comprised 98 patients whose mean age was 12.3 ± 3.8 years. Anterior uveitis was present in 52.0%, panuveitis in 37.8%, and posterior uveitis in 10.2%. The most common diagnosis was juvenile chronic iridocyclitis (JCI) (29.6%) followed by tubulointerstitial nephritis and uveitis syndrome (4.1%) and neuroretinitis (4.1%). Thirty-nine patients received systemic anti-inflammatory treatment. Among all subjects, 56% presented with ocular complications and 20% underwent ocular surgery. Visual acuity of 20/200 or less was observed in 6.2%. The common causes of decreased vision were hypotony, serous retinal detachment, and pupil disorder.Conclusions: JCI was the most common diagnosis. Hypotony, serous retinal detachment, and pupil disorder can lead to visual loss.

Long Non-coding RNAs Involved in Pathogenic Infection.

Recently developed technologies have revealed that the genomes of many organisms produce transcripts that do not encode proteins. These are called non-coding RNAs. Long non-coding RNAs (lncRNAs) are important regulators of the expression of their target genes at the levels of transcription, translation, and degradation. Multiple studies have demonstrated a role for lncRNAs in various biological responses, including pathogenic infection. Upon pathogenic infection, the expression levels of lncRNAs are dynamically altered, suggesting that lncRNAs are involved in the host immune response or propagation of pathogens. In this review, we focused on host lncRNAs that are involved in pathogenic infection. Some host lncRNAs act as host defense molecules to prevent pathogenic proliferation, while others are utilized by the pathogen to enhance the propagation of pathogens.

The Relationship between Fluorescein Angiography Leakage after Infliximab Therapy and Relapse of Ocular Inflammatory Attacks in Ocular Behçet's Disease Patients.

Purpose: To clarify the relationship between fluorescein angiography (FA) leakage after infliximab therapy and ocular attack relapse in patients with ocular Behçet's disease (BD). Methods: Patients with ocular BD were divided into two groups based on the presence (Group 1) or absence (Group 2) of ocular attacks after IFX therapy. FA leakage was evaluated by FA score in each of the optic discs, macula, large retinal vessels, and capillary vessels. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the relationship between FA score after IFX therapy and ocular attack relapse. Results: The areas under the curves obtained from the ROC curve of optic disc score and capillary vessels score after IFX therapy were 0.867 (95% confidence interval [CI]: 0.788-0.946) and 0.788 (95% CI: 0.649-0.927), respectively. Conclusions: FA leakage in the optic disc and capillary vessels after IFX therapy was strongly related to ocular attack relapse.

Long noncoding RNA U90926 is crucial for herpes simplex virus type 1 proliferation in murine retinal photoreceptor cells.

Long non-coding RNAs (lncRNAs) play vital roles in the pathogenesis of infectious diseases, but the role of lncRNAs in herpes simplex virus 1 (HSV-1) infection remains unknown. Using RNA sequencing analysis, we explored lncRNAs that were highly expressed in murine retinal photoreceptor cell-derived 661W cells infected with HSV-1. U90926 RNA (522 nucleotides) was the most upregulated lncRNA detected post HSV-1 infection. The level of U90926 RNA was continuously increased post HSV-1 infection, reaching a 100-fold increase at 24 h. Cellular fractionation showed that U90926 RNA was located in the nucleus post HSV-1 infection. Downregulation of U90926 expression by RNA interference markedly suppressed HSV-1 DNA replication (80% reduction at 12 h post infection) and HSV-1 proliferation (93% reduction at 12 h post infection) in 661W cells. The survival rates of U90926-knockdown cells were significantly increased compared to those of control cells (81% and 21%, respectively; p < 0.0001). Thus, lncRNA U90926 is crucial for HSV-1 proliferation in retinal photoreceptor cells and consequently leads to host cell death by promoting HSV-1 proliferation.

Retinal vascular inflammatory and occlusive changes in infectious and non-infectious uveitis.

PURPOSE: Retinal vasculitis and occlusive changes are important signs of posterior uveitis and are possible diagnostic markers for uveitis. However, the frequency of arteritis and phlebitis in various uveitis entities, including infectious uveitis (IU) and non-infectious uveitis (NIU), have not been systematically investigated. STUDY DESIGN: Retrospective. METHODS: We investigated the frequency of retinal vascular inflammatory and occlusive changes in patients with IU and NIU. The study included 283 patients with intermediate, posterior, or pan-uveitis who were diagnosed with IU (presumed tuberculous uveitis, acute retinal necrosis, cytomegalovirus retinitis, human T-cell lymphotropic virus type 1-associated uveitis, toxoplasmic retinitis, syphilitic uveitis, rubella virus-associated uveitis, fungal endophthalmitis, and bacterial endophthalmitis) or NIU (sarcoidosis, Behçet's disease, Vogt-Koyanagi-Harada disease, human leukocyte antigen-B27-associated uveitis, systemic lupus erythematosus retinopathy, psoriatic uveitis, rheumatoid arthritis/collagen disease-associated uveitis, multiple sclerosis-associated uveitis, and sympathetic ophthalmia). All patients underwent fluorescein angiography (FA) and color photography examinations of the fundus. Presence of inflammatory and occlusive changes was determined by FA images. RESULTS: Significantly higher positive ratios of phlebitis, vein sheathing, vein occlusion, arteritis, artery sheathing, artery occlusion, and avascular areas were observed in the IU group than in the NIU group (p < 0.05). Notably, the discrepancy between IU and NIU was prominent with regard to retinal arterial changes (arteritis [57.9% vs 11.2%], inflammatory artery sheathing [33.7% vs 0%], and artery occlusion [22.1% vs 3.7%], respectively; p < 0.0001). CONCLUSION: Findings of vasculitis and occlusion, especially in retinal arteries, in FA strongly suggest an infectious origin of active uveitis.

Analysis of inflammatory mediators in the vitreous humor of eyes with pan-uveitis according to aetiological classification.

Treatment of uveitis is complicated because of its multiple aetiologies and elevation of various inflammatory mediators. To determine the mediators that are elevated in the vitreous humor according to the aetiology of the uveitis, we examined the concentrations of 21 inflammatory cytokines, 7 chemokines, and 5 colony-stimulating/growth factors in vitreous samples from 57 eyes with uveitis associated with intraocular lymphoma (IOL, n = 13), sarcoidosis (n = 15), acute retinal necrosis (ARN, n = 13), or bacterial endophthalmitis (BE, n = 16). Samples from eyes with idiopathic epiretinal membrane (n = 15), which is not associated with uveitis, were examined as controls. Heat map analysis demonstrated that the patterns of inflammatory mediators in the vitreous humor in eyes with uveitis were disease-specific. Pairwise comparisons between the 5 diseases showed specific elevation of interferon-α2 in ARN and interleukin (IL)-6, IL-17A, and granulocyte-colony stimulating factor in BE. Pairwise comparisons between IOL, ARN, and BE revealed that levels of IL-10 in IOL, RANTES (regulated on activation, normal T cell expressed and secreted) in ARN, and IL-22 in BE were significantly higher than those in the other 2 types of uveitis. These mediators are likely to be involved in the immunopathology of specific types of uveitis and may be useful biomarkers.

Association between subfoveal choroidal thickness and leakage site on fluorescein angiography in Behçet's uveitis.

This study aimed to clarify the association between the retinal leakage site on fluorescein angiography (FA) and subfoveal choroidal thickness (SCT) measured using enhanced depth imaging optical coherence tomography (EDI-OCT). Twenty-two patients with Behçet's uveitis were retrospectively selected in this study. They underwent EDI-OCT and FA in both the active and convalescent phases. The associations of the changes between the active and convalescent phases in SCT and in FA leakage in various retinal areas (total retina, peripheral retina, macula, and optic disc) were examined. The changing rates of SCT between the two investigated phases were significantly associated with the changes in total FA leakage scores (y = 1.79X+ 11.7, r2 = 0.210, p < 0.05). Furthermore, the changes in FA leakage scores in the macula were correlated with the changing rates in SCT (y = 3.72X+ 13.9, r2 = 0.219, p < 0.05). By contrast, there were no significant associations between the changes in SCT and those in leakage from the peripheral retina or the optic disc on FA. These findings demonstrate that SCT may reflect macular vasculitis as determined using FA, and SCT measurement could be a non-invasive method to investigate inflammation near the macula in Behçet's uveitis.