Cell-Based Therapies for Glaucoma.

Glaucomatous optic neuropathy (GON) is the major cause of irreversible visual loss worldwide and can result from a range of disease etiologies. The defining features of GON are retinal ganglion cell (RGC) degeneration and characteristic cupping of the optic nerve head (ONH) due to tissue remodeling, while intraocular pressure remains the only modifiable GON risk factor currently targeted by approved clinical treatment strategies. Efforts to understand the mechanisms that allow species such as the zebrafish to regenerate their retinal cells have greatly increased our understanding of regenerative signaling pathways. However, proper integration within the retina and projection to the brain by the newly regenerated neuronal cells remain major hurdles. Meanwhile, a range of methods for in vitro differentiation have been developed to derive retinal cells from a variety of cell sources, including embryonic and induced pluripotent stem cells. More recently, there has been growing interest in the implantation of glial cells as well as cell-derived products, including neurotrophins, microRNA, and extracellular vesicles, to provide functional support to vulnerable structures such as RGC axons and the ONH. These approaches offer the advantage of not relying upon the replacement of degenerated cells and potentially targeting earlier stages of disease pathogenesis. In order to translate these techniques into clinical practice, appropriate cell sourcing, robust differentiation protocols, and accurate implantation methods are crucial to the success of cell-based therapy in glaucoma. Translational Relevance: Cell-based therapies for glaucoma currently under active development include the induction of endogenous regeneration, implantation of exogenously derived retinal cells, and utilization of cell-derived products to provide functional support.

Immunosuppressive therapy for Vogt-Koyanagi-Harada disease: a retrospective study and review of literature.

BACKGROUND: Vogt-Koyanagi-Harada (VKH) disease is an idiopathic autoimmune disease which targets melanin-containing tissues such as the uvea, meninges, ear and skin. This typically presents in the eye with acute findings of granulomatous anterior uveitis, diffuse choroidal thickening, multiple focal areas of sub-retinal fluid and, in severe cases, optic nerve involvement with bullous serous retinal detachment can occur. Early initiation of treatment has been advocated to prevent progression to the chronic stage of the disease, which can result to a sunset glow fundus with devastatingly poor visual outcome. Treatment is usually initiated with corticosteroids followed by an early introduction of immunosuppressive treatment (IMT) to achieve immediate response after disease presentation, although the choice of IMT for VKH can vary. MAIN FINDINGS: We conducted a retrospective case-series to investigate the management trend of treating VKH over a 20-year period. Twenty-six patients were included and we found a shift from steroid monotherapy to combined IMT/low-dose steroid for the management of acute initial-onset of VKH in the last 10 years. Our average time from diagnosis to initiation of IMT was 2.1 months. 81% (21 of 26 patients) of our patients treated with combined IMT/steroid were able to achieve disease stability with significant good visual outcome at 24 months (Median VApre-IMT = 0.3 Logmar vs VApost-IMT = 0.0 Logmar, p = 0.0001). MMF monotherapy was the most common IMT used and it was well-tolerated by our patients. Even so, 50% of our patients who were treated with MMF did not achieve disease control. We then performed a literature review to identify any IMT which could be superior in the treatment of VKH. We also share our experience (where applicable) on the various treatment options found from the literature review. SHORT CONCLUSION: Our study found that patients with VKH who were treated with combined IMT/low-dose steroids achieved significantly better visual improvement at 24 months compared to steroid monotherapy. We frequently chose MMF and this appears to be well tolerated by our patients. Since its introduction, anti-TNF agents are increasingly becoming a popular choice of treatment for VKH as these have been shown to be safe and effective. However, more data is required to provide evidence that anti-TNF agents can be used as first-line treatment and as monotherapy.

Transcriptomics of CD29+/CD44+ cells isolated from hPSC retinal organoids reveals a single cell population with retinal progenitor and Müller glia characteristics.

Müller glia play very important and diverse roles in retinal homeostasis and disease. Although much is known of the physiological and morphological properties of mammalian Müller glia, there is still the need to further understand the profile of these cells during human retinal development. Using human embryonic stem cell-derived retinal organoids, we investigated the transcriptomic profiles of CD29+/CD44+ cells isolated from early and late stages of organoid development. Data showed that these cells express classic markers of retinal progenitors and Müller glia, including NFIX, RAX, PAX6, VSX2, HES1, WNT2B, SOX, NR2F1/2, ASCL1 and VIM, as early as days 10-20 after initiation of retinal differentiation. Expression of genes upregulated in CD29+/CD44+ cells isolated at later stages of organoid development (days 50-90), including NEUROG1, VSX2 and ASCL1 were gradually increased as retinal organoid maturation progressed. Based on the current observations that CD24+/CD44+ cells share the characteristics of early and late-stage retinal progenitors as well as of mature Müller glia, we propose that these cells constitute a single cell population that upon exposure to developmental cues regulates its gene expression to adapt to functions exerted by Müller glia in the postnatal and mature retina.

Predictive Factors for Magnetic Resonance Imaging Changes Suggestive of Demyelination in Adult Patients with Uveitis Scanned Prior to Commencing Adalimumab Therapy.

PURPOSE: To report the predictive clinical factors for abnormal magnetic resonance imaging (MRI) scans suggestive of demyelination by analysis of MRI's performed for adult non-infectious uveitic patients prior to commencing adalimumab therapy. METHODS: Retrospective case review of 240 patients was conducted in a single tertiary institution between November 2017 and March 2020. Aetiology of underlying disease, clinical characteristics, and MRI outcomes were analysed. RESULTS: The presence of bilateral idiopathic intermediate uveitis (IIU) (p = .0048) and neurological symptoms (p = .028) were highly predictive of an abnormal MRI strongly suggestive of demyelination (MRSSD); 5 out of 64 scans (7.8%) with these clinical characteristics had MRSSD. CONCLUSIONS: Tumor necrosis factor antagonist-induced demyelination is a concern in adalimumab use. We propose an MRI screening protocol to identify those at high risk of demyelination; positive results can be maximised by screening all patients with IIU and those with neurological symptoms.

MicroRNA profile of extracellular vesicles released by Müller glial cells.

Introduction: As with any other radial glia in the central nervous system, Müller glia derive from the same neuroepithelial precursors, perform similar functions, and exhibit neurogenic properties as radial glia in the brain. Müller glial cells retain progenitor-like characteristics in the adult human eye and can partially restore visual function upon intravitreal transplantation into animal models of glaucoma. Recently, it has been demonstrated that intracellular communication is possible via the secretion of nano-sized membrane-bound extracellular vesicles (EV), which contain bioactive molecules like microRNA (miRNA) and proteins that induce phenotypic changes when internalised by recipient cells. Methods: We conducted high-throughput sequencing to profile the microRNA signature of EV populations secreted by Müller glia in culture and used bioinformatics tools to evaluate their potential role in the neuroprotective signalling attributed to these cells. Results: Sequencing of miRNA within Müller EV suggested enrichment with species associated with stem cells such as miR-21 and miR-16, as well as with miRNA previously found to play a role in diverse Müller cell functions in the retina: miR-9, miR-125b, and the let-7 family. A total of 51 miRNAs were found to be differentially enriched in EV compared to the whole cells from which EV originated. Bioinformatics analyses also indicated that preferential enrichment of species was demonstrated to regulate genes involved in cell proliferation and survival, including PTEN, the master inhibitor of the PI3K/AKT pathway. Discussion: The results suggest that the release by Müller cells of miRNA-enriched EV abundant in species that regulate anti-apoptotic signalling networks is likely to represent a significant proportion of the neuroprotective effect observed after the transplantation of these cells into animal models of retinal ganglion cell (RGC) depletion. Future studies will seek to evaluate the modulation of putative genes as well as the activation of these pathways in in vitro and in vivo models following the internalisation of Müller-EV by target retinal neurons.

Evaluation of fluocinolone acetonide 0.19 mg intravitreal implant in the management of birdshot retinochoroiditis.

PURPOSE: To report treatment outcomes and efficacy of the fluocinolone acetonide 0.19 mg intravitreal implant (Iluvien) in controlling retinal and choroidal inflammation in 11 patients with birdshot retinochoroiditis. METHODS: A single-centre, retrospective, interventional case series. The primary efficacy end point was improvement in vascular leakage on fluorescein angiography (FA), effect on cystoid macular oedema (CMO) and resolution of hypofluorescent lesions on indocyanine green angiography (ICGA); secondary measures were improvements on pattern and full-field electroretinogram (PERG; ERG) parameters. Safety outcome measures were intraocular elevation and cataractogenesis. RESULTS: Fifteen eyes received Iluvien implant with an average follow-up of 31 months (range 12-36 months). Prior to the implant, 5 (33.3%) eyes had received dexamethasone intravitreal implant 0.7 mg (Ozurdex). FA showed evidence of vascular leakage in all eyes at baseline. Between month 6 and 12, FA showed that 73.4% of eyes had no leakage, this increased to 84.6% by month 24. Three eyes in our study had CMO at baseline. 6 months after Iluvien implant, all eyes achieved complete CMO resolution. One year after insertion of the implant, the characteristic hypofluorescent lesions on ICGA were unchanged in all cases. There was baseline ERG evidence indicating a high incidence of peripheral cone system dysfunction and most showed PERG evidence of macular dysfunction. Retinal function improved and macular function improved or was stable in the majority following treatment. CONCLUSIONS: The results show the possible therapeutic effect of Iluvien in the management of Birdshot-related vascular leakage, CMO and retinal dysfunction. However, choroidal lesions seem to persist with no detectable response to treatment.

Efficacy of Tacrolimus in Uveitis, and the Usefulness of Serum Tacrolimus Levels in Predicting Disease Control. Results from a Single Large Center.

AIMS: To evaluate the efficacy of tacrolimus in patients with noninfectious uveitis, as well as the usefulness of serum tacrolimus concentration measurements in predicting disease control. METHODS: A retrospective review was carried out on 71 eligible patients from a single specialist uveitis center for minimum 1-year follow-up. Analysis was carried out on disease activity, visual acuity, and trough serum tacrolimus concentrations (STC). RESULTS: At 1-year follow-up, disease control was achieved in 49 patients (69.0%), this was significantly more likely in patients with trough STC levels above 5 ng/mL (88% vs 53%, p = .002). There was a significant reduction in oral prednisolone (dose ≥7.5 mg, 86% vs 54%, p < .0001). Tacrolimus was discontinued in 12 patients (17%) due to side effects. DISCUSSION: In this study cohort, oral tacrolimus was effective and well tolerated in the treatment of noninfectious uveitis. Trough STC between 5 ng/mL and 10 ng/ml was associated with better disease control at 1-year follow-up.

Ocular toxoplasmosis: phenotype differences between toxoplasma IgM positive and IgM negative patients in a large cohort.

PURPOSE: To investigate the differences in demographics and clinical characteristics of patients diagnosed with ocular toxoplasmosis according to their IgM status. METHODS: Retrospective case note analysis was carried out on patients who tested positive for serum Toxoplasma gondii-specific IgM antibodies (IgM+) as well as a comparator group who tested negative for serum IgM (IgM-), but positive for serum IgG. Patient demographics and clinical features were compared between the two groups to evaluate for any significant differences. RESULTS: One hundred and six patients were included in the study between March 2011 and June 2018, consisting of 37 in the IgM +group and 69 in the IgM- group. Patients in the IgM +group were significantly older (51.1 vs 34.1 years, p<0.0001), more likely to present with central macular lesions (32% vs 12%, p=0.012), and more likely to develop rhegmatogenous retinal detachment (11% vs 1%, p=0.049). In contrast, patients in the IgM- group were more likely present with pain (20% vs 3%, 0.017) and exhibit more severe inflammation of the anterior chamber and vitreous (p<0.05). Overall, retinal lesions were more likely to be superotemporal (55%) and superonasal (31%). Furthermore, age was associated with larger (p=0.003) and more peripheral lesions (p=0.007). CONCLUSIONS: This study demonstrated significant differences in clinical characteristics of ocular toxoplasmosis according to serum IgM status. IgM+ patients were older, less likely to report pain, had lower levels of intraocular inflammation, but were more likely to have macular involvement. We also found age to be correlated with larger and more peripheral lesions.

Strain Specific Responses in a Microbead Rat Model of Experimental Glaucoma.

PURPOSE: A major challenge in glaucoma research is the lack of reproducible animal models of RGC and optic nerve damage, the characteristic features of this condition. We therefore examined the glaucomatous responses of two different rat strains, the Brown Norway (BN) and Lister Hooded (LH) rats, to high intraocular pressure (IOP) induced by injection of magnetic beads into the anterior chamber. METHODS: Magnetic microsphere suspensions (20 µl of 5-20 mg/ml) were injected into the anterior chamber of BN (n = 9) or LH (N = 15) rats. Animals from each strain were divided into three groups, each receiving a different dose of microspheres. IOP was measured over 4 weeks using a rebound tonometer. Retinal ganglion cell (RGC) damage and function were assessed using scotopic electroretinograms (ERGs), retinal flatmounts and optic nerve histology. ANOVA and Student's t-tests were used to analyse the data. RESULTS: A significant elevation in IOP was observed in BN rats receiving injections of 20 mg (37.18 ± 12.28 mmHg) or 10 mg microspheres/ml (36.95 ± 13.63 mmHg) when compared with controls (19.63 ± 4.29 mmHg) (p < .001) over 2 weeks. This correlated with a significant impairment of RGC function, as determined by scotopic ERG (p < .001), reduction in axon number (p < .05) and lower RGC density (P < .05) in animals receiving 20 mg or 10 mg microspheres/ml as compared with controls. LH rats receiving similar microsphere doses showed reduced scotopic ERG function (p < .001) after 2 weeks. No changes in IOP was seen in this strain, although a reduction in axon density was observed in optic nerve cross-sections (p < .05). Initial changes in IOP and ERG responses observed in BN rats remained unchanged for a duration of 7 weeks. In LH animals, ERG responses were decreased at 1-2 weeks and returned to control levels after 5 weeks. CONCLUSIONS: Although this model was easily reproducible in BN rats, the phenotype of injury observed in LH rats was very different from that observed in BN animals. We suggest that differences in the glaucomatous response observed in these two strains may be ascribed to anatomical and physiological differences and merits further investigation.

Galectins and their involvement in ocular disease and development.

Galectins are carbohydrate binding proteins with high affinity to ß-galactoside containing glycoconjugates. Understanding of the functions of galectins has grown steadily over the past decade, as a result of substantial advancements in the field of glycobiology. Galectins have been shown to be versatile molecules that participate in a range of important biological systems, including inflammation, neovascularisation and fibrosis. These processes are of particular importance in ocular tissues, where a major theme of recent research has been to divert diseases away from pathways which result in loss of function into pathways of repair and regeneration. This review summarises our current understanding of galectins in the context important ocular diseases, followed by an update on current clinical studies and future directions.

The Risk of Posterior Capsule Rupture during Phacoemulsification Cataract Surgery in Eyes with Previous Intravitreal Anti Vascular Endothelial Growth Factor Injections.

PURPOSE: To investigate if previous intravitreal anti vascular endothelial growth factor (VEGF) injections are a predictor for posterior capsule rupture (PCR) during phacoemulsification cataract surgery. SETTING: National Health Service: Whipps Cross University Hospital Eye Treatment Centre. District General, London, United Kingdom DESIGN:: Single centre, retrospective, electronic medical record (EMR) database study with univariate analysis. METHODS: EMR (Medisoft) was used to extract data for eyes undergoing phacoemulsification surgery between 01.08.16 to 01.01.18. Patient demographics, indication for intravitreal therapy, treatment type, number of previous intravitreal injections (IVI), diabetic status, surgeon grade and operative complications were included as variables for analysis. RESULTS: Data was available for 4047 cataract operations. Of these, 108 had undergone previous anti-VEGF IVI treatment. Three eyes were noted to have pre-operative PC trauma and were excluded from the final analysis. The logistic regression analysis after exclusion of the eyes with pre-existing damage to the PC confirmed that prior anti-VEGF IVI treatment was associated with an increased risk of PCR when compared to the non IVI group (9.26% vs 1.88%, p<0.0001). There is a dose dependent relationship between the number of anti-VEGF injections and the likelihood of PCR. CONCLUSIONS: Previous intravitreal anti-VEGF injections are significantly correlated with an increased risk of surgical PCR despite the absence of visible structural damage to the PC pre-operatively.

Risk of posterior capsular rupture during phacoemulsification cataract surgery in eyes with previous intravitreal antivascular endothelial growth factor injections.

PURPOSE: To investigate whether previous intravitreal antivascular endothelial growth factor (VEGF) injections are a predictor for posterior capsular rupture (PCR) during phacoemulsification cataract surgery. SETTING: Whipps Cross University Hospital Eye Treatment Centre, London, United Kingdom. DESIGN: Single-center, retrospective, electronic medical record (EMR) database study with univariate analysis. METHODS: Data were extracted from an EMR system on eyes undergoing phacoemulsification surgery between August 1, 2016, and January 1, 2018. Patient demographics, indication for intravitreal therapy, treatment type, the number of previous intravitreal injections (IVIs), diabetic status, surgeon grade, and operative complications were included as variables for analysis. RESULTS: Data were available for 4047 cataract operations. Of these, 108 (2.7%) had undergone previous anti-VEGF IVI treatment. Three eyes were noted to have preoperative PC trauma and were excluded from the final analysis. The logistic regression analysis after exclusion of the eyes with pre-existing damage to the PC confirmed that previous anti-VEGF IVI treatment was associated with an increased risk of PCR when compared with the non-IVI group (6.67% vs 1.88%, P < .0001). There is a dose-dependent relationship between the number of anti-VEGF injections and the likelihood of PCR. CONCLUSIONS: Previous intravitreal anti-VEGF injections are significantly correlated with an increased risk of surgical PCR, despite the absence of visible structural damage to the posterior capsule preoperatively.

Potential of Müller Glia for Retina Neuroprotection.

Müller glia constitute the main glial cells of the retina. They are spatially distributed along this tissue, facilitating their close membrane interactions with all retinal neurons. Müller glia are characterized by their active metabolic functions, which are neuroprotective in nature. Although they can become reactive under pathological conditions, leading to their production of inflammatory and neurotoxic factors, their main metabolic functions confer neuroprotection to the retina, resulting in the promotion of neural cell repair and survival. In addition to their protective metabolic features, Müller glia release several neurotrophic factors and antioxidants into the retinal microenvironment, which are taken up by retinal neurons for their survival. This review summarizes the Müller glial neuroprotective mechanisms and describes advances made on the clinical application of these factors for the treatment of retinal degenerative diseases. It also discusses prospects for the use of these cells as a vehicle to deliver neuroprotective factors into the retina.

Patient-reported outcome measuring tools in cataract surgery: Clinical comparison at a tertiary hospital.

PURPOSE: To assess the performance of patient-reported outcome measure questionnaires and determine their appropriateness for routine use in cataract patients. SETTING: Moorfields Eye Hospital, London, United Kingdom. DESIGN: Prospective cohort study. METHODS: Patients having cataract surgery between February and March 2013 were recruited. The following 4 questionnaires-Catquest-9SF, EuroQol 5-dimensions questionnaire (EQ-5D) and visual analog scale (EQ-VAS), National Eye Institute Socioemotional Scale (NEI-SES), and short-form Visual Function Index (VF-8R)-were completed preoperatively and 3 weeks and 3 months postoperatively. The questionnaires' performances were then compared. The paired Student t test and Pearson correlations were used for statistical analysis. RESULTS: One hundred twenty-two patients were recruited; 67.2% and 61.8% completed 3-week and 3-month follow-up, respectively. The changes in the mean scores for the Catquest-9SF, EQ-5D, EQ-VAS, NEI-SES, and VF-8R at 3 weeks were 120.86% (P < .0001), 1.61% (P = .61), 3.37% (P = .09), 16.12% (P = .12), and 61.76 % (P < .0001), respectively. At 3 months, the changes were 162.42% (P < .0001), 4.54% (P = .16), 4.84% (P = .09), 54.63% (P < .0001), and 87.55% (P < .0001), respectively. Correlations between patient-reported outcome measure questionnaires and visual acuity measures were variable and weak at best. CONCLUSIONS: It is feasible to assess patient-reported outcomes in cataract surgery as part of routine clinical practice. In addition, visual acuity might not fully reflect patients' visual function. Clinicians should consider using patient-reported outcome measure questionnaires to facilitate surgical decision-making and outcome monitoring. FINANCIAL DISCLOSURE: None of the authors has a financial or proprietary interest in any material or method mentioned.

Poppers retinopathy.

We present a case of a 52-year-old man with sudden, bilateral central loss of vision as a result of inhalation of 'poppers'. He was found to have characteristic changes on optical coherence tomography. With conservative treatment, the patient's vision improved marginally at 3 months follow-up. An overview of previous published cases is also included.

Leiomyosarcoma of the small bowel: Report of a case and review of the literature.

INTRODUCTION: Leiomyosarcoma of the small bowel is an extremely rare form of gastrointestinal malignancy. Small bowel tumours are usually asymptomatic at the early stages, and difficult to visualise by upper and lower endoscopy. PRESENTATION OF CASE: An 83-year-old gentleman presented in surgical outpatient clinic with chronic anaemia, abdominal discomfort and a single episode of malaena. Initial OGD and colonoscopy were both unremarkable. Subsequent CT revealed a mass in the right iliac fossa of likely small bowel origin, leading to an urgent laparotomy and resection with primary anastomosis. Histopathology showed a high grade leiomyosarcoma with no signs of metastasis and confirmatory immunological staining. Post-surgery follow up remains unremarkable. DISCUSSION: Leiomyosarcomas of the small bowel are extremely rare entities, particularly following the advent of robust immunohistological diagnostic methods allowing differentiation from GISTs. As small bowel tumours are often not visualised by upper and lower endoscopy, further investigations to visualise the small bowel are crucial, generally in the form of magnetic resonance enterography, CT colonography or wireless capsule endoscopy. CONCLUSION: The treatment of such tumours remains predominantly centred around surgical resection, and prognosis is dependent on tumour size and histological staging.