Retinal pigment epithelium exhibits gene expression and phagocytic activity alterations when exposed to retinoblastoma chemotherapeutics.

Retinoblastoma (Rb) is a rare malignant disorder affecting the developing retina of children under the age of five. Chemotherapeutic agents used for treating Rb have been associated with defects of the retinal pigment epithelium (RPE), such as hyperplasia, gliosis, and mottling. Herein, we have developed two pluripotent stem cell (PSC)-RPE models to assess the cytotoxicity of known Rb chemotherapeutics such as Melphalan, Topotecan and TW-37. Our findings demonstrate that these drugs alter the RPE by decreasing the monolayer barrier's trans-epithelial resistance and affecting the cells' phagocytic activity. Transcriptional analyses demonstrate an altered expression of genes involved in melanin and retinol processing, tight junction and apical-basal polarity pathways in both models. When applied within the clinical range, none of the drug treatments caused significant cytotoxic effects, changes to the apical-basal polarity, tight junction network or cell cycle. Together, our results demonstrate that although the most commonly used Rb chemotherapeutic drugs do not cause cytotoxicity in RPE, their application in vitro leads to compromised phagocytosis and strength of the barrier function, in addition to changes in gene expression that could alter the visual cycle in vivo. Our data demonstrate that widely used Rb chemotherapeutic drugs can have a deleterious impact on RPE cells and thus great care has to be exercised with regard to their delivery so the adjacent healthy RPE is not damaged during the course of tumor eradication.

Ectopic lens material in an otherwise healthy 5-week-old infant.

PURPOSE: To report the unusual finding of ectopic lens material in an otherwise healthy 5-week-old infant. METHODS: Case report and literature review. RESULTS: An asymptomatic 5-week-old female infant was found to have unilateral ectopic lens material in the retrolental space of the left eye associated with a posterior capsular defect. CONCLUSION: The abnormality is likely embryological in origin, and the established progression for similar conditions means long-term monitoring is required to ensure the best possible visual outcome.

How to use the direct ophthalmoscope.

Ophthalmoscopy and red reflex examination are core medical skills required to identify sight-threatening and life-threatening disease. We discuss the predictive utility and limitations of findings with an ophthalmoscope and tips as to how to optimise these. We outline important considerations in three clinical scenarios: an abnormal red reflex, an abnormal optic disc and retinal haemorrhages in the context of child protection concerns.

Surrogate Outcome Measures for Corneal Neurotization in Infants and Children.

BACKGROUND: Corneal anesthesia is a rare and challenging condition, particularly in young children. The insensate cornea leads to abnormal epithelial cell metabolism and loss of trophic influences supplied by the corneal nerve fibers. This results in recurrent spontaneous epithelia erosion and eventual loss of sight. Corneal reinnervation is a definitive treatment option for neuropathic keratitis. The outcome measures in young children following corneal sensitization are different to adults as esthesiometry is unachievable. METHODS: The authors have undertaken corneal reinnervation in a young patient using a sural nerve graft. Surrogate measures suitable for pediatric patients were used for assessment of the outcome. RESULTS: Postoperatively there was evidence of improved corneal healing and function after 8 weeks. At 10 months postprocedure, the cornea was completely free of vascularization. CONCLUSION: Resensitization of the cornea using nerve grafts has previously been reported in older children and adults. This is the first time the procedure has been undertaken in a young child. Although the technique is still in its infancy with only 4 patients reported worldwide including our report, it seems to hold promise of improvement to this challenging cohort of patients.

Metabolite profiling in retinoblastoma identifies novel clinicopathological subgroups.

BACKGROUND: Tumour classification, based on histopathology or molecular pathology, is of value to predict tumour behaviour and to select appropriate treatment. In retinoblastoma, pathology information is not available at diagnosis and only exists for enucleated tumours. Alternative methods of tumour classification, using noninvasive techniques such as magnetic resonance spectroscopy, are urgently required to guide treatment decisions at the time of diagnosis. METHODS: High-resolution magic-angle spinning magnetic resonance spectroscopy (HR-MAS MRS) was undertaken on enucleated retinoblastomas. Principal component analysis and cluster analysis of the HR-MAS MRS data was used to identify tumour subgroups. Individual metabolite concentrations were determined and were correlated with histopathological risk factors for each group. RESULTS: Multivariate analysis identified three metabolic subgroups of retinoblastoma, with the most discriminatory metabolites being taurine, hypotaurine, total-choline and creatine. Metabolite concentrations correlated with specific histopathological features: taurine was correlated with differentiation, total-choline and phosphocholine with retrolaminar optic nerve invasion, and total lipids with necrosis. CONCLUSIONS: We have demonstrated that a metabolite-based classification of retinoblastoma can be obtained using ex vivo magnetic resonance spectroscopy, and that the subgroups identified correlate with histopathological features. This result justifies future studies to validate the clinical relevance of these subgroups and highlights the potential of in vivo MRS as a noninvasive diagnostic tool for retinoblastoma patient stratification.

Long-term retinoblastoma follow-up with or without general anaesthesia.

BACKGROUND: Children with treated retinoblastoma undergo frequent examinations to monitor for recurrent or new tumours. Examinations under anaesthesia allow a more complete examination in younger children, however they are stressful for the family, subject the child to medical risk and consume resources. The risk of recurrent or new tumours declines with age and it is common practice to examine older children without general anaesthesia. There are no studies on the safety and cost effectiveness of this practice, or guidelines on when examination without anaesthesia (EWA) can be safely commenced. PROCEDURE: Retrospective case note review of 128 sequential patients treated for retinoblastoma in a national referral centre over 10 years. RESULTS: Following exclusions, 113 eyes of 84 children were analysed. The mean age at diagnosis was 20 months (range birth to 71 months). There were 55 unilateral and 29 bilateral cases. The mean follow-up was 77.7 months (range 12-178 months). EWA was commenced at a mean age of 53 months (range 12-98 months). The age of conversion to EWA was largely dependent on child cooperation and disease activity. Tumour activity was detected on EWA in one child at the age of 86 months, 9 months after the last active treatment and treated successfully. CONCLUSIONS: Examination without general anaesthesia does not appear to expose children to an increased risk of undetected tumour growth. This study highlights the important factors to be considered when deciding a safe time to commence EWA.

Use of cyanoacrylate glue for temporary tarsorrhaphy in children.

PURPOSE: Congenital anophthalmia and postenucleation socket contracture are difficult conditions that require serial socket expansion with the use of hydrogel expanders and custom-made conformers along with temporary tarsorrhaphy. METHODS: The authors undertook a part prospective case review of all children undergoing temporary tarsorrhaphy using cyanoacrylate glue over a 3-year period at a tertiary specialist children's hospital. RESULTS: They report a series of 7 children undergoing temporary tarsorrhaphy with cyanoacrylate glue instead of the conventional suturing technique. Indications were socket expansion (n = 4), fornix deepening (n = 2), prosthesis reposition, and prolapsed conjunctiva following enucleation (n = 1).The age range was 3 weeks to 14 years (mean, 2.7 years). The glue tarsorrhaphy lasted between 0.5 and 13 weeks (mean, 4.5 weeks). There were no adverse outcomes, and the glue tarsorrhaphy was tolerated well in all cases, with relative ease of reapplication of glue in clinic. CONCLUSIONS: Their study demonstrates that this technique allows quick and efficient temporary tarsorrhaphy with relative ease of reapplication in a clinic setting, avoiding the need for multiple general anesthetics.

Genetic Diagnosis of Retinoblastoma Using Aqueous Humour-Findings from an Extended Cohort.

The identification of somatic RB1 variation is crucial to confirm the heritability of retinoblastoma. We and others have previously shown that, when tumour DNA is unavailable, cell-free DNA (cfDNA) derived from aqueous humour (AH) can be used to identify somatic RB1 pathogenic variation. Here we report RB1 pathogenic variant detection, as well as cfDNA concentration in an extended cohort of 75 AH samples from 68 patients. We show cfDNA concentration is highly variable and significantly correlated with the collection point of the AH. Cell-free DNA concentrations above 5 pg/µL enabled the detection of 93% of known or expected RB1 pathogenic variants. In AH samples collected during intravitreal chemotherapy treatment (Tx), the yield of cfDNA above 5 pg/µL and subsequent variant detection was low (≤46%). However, AH collected by an anterior chamber tap after one to three cycles of primary chemotherapy (Dx1+) enabled the detection of 75% of expected pathogenic variants. Further limiting our analysis to Dx1+ samples taken after ≤2 cycles (Dx ≤ 2) provided measurable levels of cfDNA in all cases, and a subsequent variant detection rate of 95%. Early AH sampling is therefore likely to be important in maximising cfDNA concentration and the subsequent detection of somatic RB1 pathogenic variants in retinoblastoma patients undergoing conservative treatment.

Emerging New Therapeutics for Retinoblastoma.

Background: Over the last few decades, chemotherapy has become the main treatment of retinoblastoma, delivered through various routes: intravenous, intra-arterial, and intravitreal. Despite its efficacy, chemotherapy-related toxicity (ocular and systemic) and recurrences due to resistant tumor clones are common, highlighting the need for novel therapeutic agents. Summary: Recent advances in our understanding of the molecular drivers of Rb1 tumorigenesis and mechanisms of tumor resistance have afforded opportunities to explore novel targets such as the MDMX-p53 pathway (nutlin-3), histone deacetylase inhibitors, spleen tyrosine kinase inhibitors, and genetic and immune modulatory drugs. In this review, we discuss the limitations of current therapeutic strategies, candidate cellular pathways, current evidence for newer targeted drugs, and offer a look toward the future. Key Messages: Advances in the understanding of the molecular drivers of the RB pathway have provided opportunities to explore novel drugs with targeted effects, improved bioavailability, and reduced chemotoxicity.

Outcomes following tacrolimus systemic immunosuppression for penetrating keratoplasty in infants and young children.

OBJECTIVE: To report outcomes of tacrolimus immunosuppression after penetrating keratoplasty (PK) in very young children. METHODS: Retrospective, consecutive, cohort study of children undergoing PK at a tertiary children's hospital between 2005 and 2016. Oral tacrolimus immunosuppression was given for 2 years, followed by topical tacrolimus. RESULTS: Fourteen children (20 eyes) had 24 PKs; nineteen eyes had primary PKs, five eyes had repeat PKs. Mean age at primary graft was 95 days (3.1 months) for anterior segment dysgenesis (ASD), 430 days (14.3 months) for non-ASD children. Eleven children (15 eyes) had ASD. Three children (five eyes) had non-ASD: two children (three eyes) had glaucoma-related corneal opacity and one child (two eyes) had congenital hereditary endothelial dystrophy (CHED). One-year rejection-free survival rates following primary PK was 80% for ASD (n = 15) and 100% for non-ASD (n = 4). At final review, 5/15 of primary grafts for ASD were clear. 10/15 failed after a mean of 19 months, specifically attributable to infection (n = 2), rejection (n = 2) and glaucoma (n = 2). 4/4 primary non-ASD grafts are clear at final review (mean follow-up = 77 months). All repeat grafts (n = 5), failed after a mean of 38.25 months. Considering all grafts, 15/24 (62.5%) failed: 5/15 due to infection, 2/15 due to rejection, 8/15 due to glaucoma, phthisis, perforation or vascularised with no rejection. At last review (mean = 58.1 months, range 28-84), overall cohort survival is 37.5%. Final visual acuities range between 0.86 and 2.4 LogMAR. CONCLUSION: We compare our results to published literature: 1-year graft survival was higher than previously reported, with lower failure due to rejection. Overall infection rates did not increase, however, proportionally, severe infections were higher. Overall graft survival is at least comparable to reported literature.

pRB-Depleted Pluripotent Stem Cell Retinal Organoids Recapitulate Cell State Transitions of Retinoblastoma Development and Suggest an Important Role for pRB in Retinal Cell Differentiation.

Retinoblastoma (Rb) is a childhood cancer of the developing retina, accounting for up to 17% of all tumors in infancy. To gain insights into the transcriptional events of cell state transitions during Rb development, we established 2 disease models via retinal organoid differentiation of a pRB (retinoblastoma protein)-depleted human embryonic stem cell line (RB1-null hESCs) and a pRB patient-specific induced pluripotent (iPSC) line harboring a RB1 biallelic mutation (c.2082delC). Both models were characterized by pRB depletion and accumulation of retinal progenitor cells at the expense of amacrine, horizontal and retinal ganglion cells, which suggests an important role for pRB in differentiation of these cell lineages. Importantly, a significant increase in the fraction of proliferating cone precursors (RXRγ+Ki67+) was observed in both pRB-depleted organoid models, which were defined as Rb-like clusters by single-cell RNA-Seq analysis. The pRB-depleted retinal organoids displayed similar features to Rb tumors, including mitochondrial cristae aberrations and rosette-like structures, and were able to undergo cell growth in an anchorage-independent manner, indicative of cell transformation in vitro. In both models, the Rb cones expressed retinal ganglion and horizontal cell markers, a novel finding, which could help to better characterize these tumors with possible therapeutic implications. Application of Melphalan, Topotecan, and TW-37 led to a significant reduction in the fraction of Rb proliferating cone precursors, validating the suitability of these in vitro models for testing novel therapeutics for Rb.

Defining High-risk Retinoblastoma: A Multicenter Global Survey.

IMPORTANCE: High-risk histopathologic features of retinoblastoma are useful to assess the risk of systemic metastasis. In this era of globe salvage treatments for retinoblastoma, the definition of high-risk retinoblastoma is evolving. OBJECTIVE: To evaluate variations in the definition of high-risk histopathologic features for metastasis of retinoblastoma in different ocular oncology practices around the world. DESIGN, SETTING, AND PARTICIPANTS: An electronic web-based, nonvalidated 10-question survey was sent in December 2020 to 52 oncologists and pathologists treating retinoblastoma at referral retinoblastoma centers. INTERVENTION: Anonymized survey about the definition of high-risk histopathologic features for metastasis of retinoblastoma. MAIN OUTCOMES AND MEASURES: High-risk histopathologic features that determine further treatment with adjuvant systemic chemotherapy to prevent metastasis. RESULTS: Among the 52 survey recipients, the results are based on the responses from 27 individuals (52%) from 24 different retinoblastoma practices across 16 countries in 6 continents. The following were considered to be high-risk features: postlaminar optic nerve infiltration (27 [100%]), involvement of optic nerve transection (27 [100%]), extrascleral tissue infiltration (27 [100%]), massive (≥3 mm) choroidal invasion (25 [93%]), microscopic scleral infiltration (23 [85%]), ciliary body infiltration (20 [74%]), trabecular meshwork invasion (18 [67%]), iris infiltration (17 [63%]), anterior chamber seeds (14 [52%]), laminar optic nerve infiltration (13 [48%]), combination of prelaminar and laminar optic nerve infiltration and minor choroidal invasion (11 [41%]), minor (<3 mm) choroidal invasion (5 [19%]), and prelaminar optic nerve infiltration (2 [7%]). The other histopathologic features considered high risk included Schlemm canal invasion (4 [15%]) and severe anaplasia (1 [4%]). Four respondents (15%) said that the presence of more than 1 high-risk feature, especially a combination of massive peripapillary choroidal invasion and postlaminar optic nerve infiltration, should be considered very high risk for metastasis. CONCLUSIONS AND RELEVANCE: Responses to this nonvalidated survey conducted in 2020-2021 showed little uniformity in the definition of high-risk retinoblastoma. Postlaminar optic nerve infiltration, involvement of optic nerve transection, and extrascleral tumor extension were the only features uniformly considered as high risk for metastasis across all oncology practices. These findings suggest that the relevance about their value in the current scenario with advanced disease being treated conservatively needs further evaluation; there is also a need to arrive at consensus definitions and conduct prospective multicenter studies to understand their relevance.

Long-term Efficacy of Mitomycin C Augmented Trabeculectomy in a Mixed Pediatric Glaucoma Cohort.

PRECIS: This paper reports a retrospective consecutive case series investigating the efficacy of Mitomycin C-augmented trabeculectomy in the treatment of primary and secondary pediatric glaucoma in a mixed etiology, multiethnic cohort of patients. PURPOSE: To evaluate the long-term efficacy and safety of Mitomycin C-augmented trabeculectomy in a mixed, tertiary-referral, pediatric glaucoma cohort. METHODS: Retrospective consecutive review of all children (37 eyes) undergoing Mitomycin C-augmented trabeculectomy by a single surgeon between 2008 and 2016. Seventeen eyes (45.9%) had primary congenital glaucoma, and 20 eyes (54.1%) had secondary glaucoma. The median age at surgery was 11 months (range, 2 to 146). The mean follow-up was 69.2±4.7 months (range, 3.5 to 107.9). RESULTS: Overall, trabeculectomy was successful in 80.6% of eyes at 12 months, 60.5% at 3 years, and 57.5% at 5 years. 45.9% cases (17 eyes) required further laser or surgery for uncontrolled intraocular pressure (IOP) and were therefore deemed as failures. The time to failure ranged from 0.4 to 65.1 months (mean, 22.2±5.1 mo). The proportion of children achieving visual acuity of 1.0 LogMAR equivalent or better increased from 43.2% preoperatively to 63.6% at 1 year and 68% at 5 years. The mean IOP reduced from 24.85±0.88 mm Hg preoperatively to 15.14±0.94 mm Hg at 3 months (39% reduction) and 17.42±1.08 mm Hg at 5 years (30% reduction). IOP-lowering medication requirement reduced from 4.14±0.20 agents preoperatively to 0.84±0.22 at 3 months (80% reduction) and 1.78±0.36 at 5 years (57% reduction). There were no sight-threatening complications such as hyphaema, bleb leak, chronic hypotony, endophthalmitis, retinal detachment, or loss of light perception. CONCLUSIONS: This study provides valuable evidence that Mitomycin C-augmented trabeculectomy is safe and effective as a treatment of primary or secondary pediatric glaucoma, with particularly encouraging results in cases of secondary glaucoma. Trabeculectomy offers the potential for delaying or avoiding glaucoma drainage device surgery in a significant proportion of children.

Dissecting the Transcriptional and Chromatin Accessibility Heterogeneity of Proliferating Cone Precursors in Human Retinoblastoma Tumors by Single Cell Sequencing-Opening Pathways to New Therapeutic Strategies?

Purpose: Retinoblastoma (Rb) is a malignant neoplasm arising during retinal development from mutations in the RB1 gene. Loss or inactivation of both copies of RB1 results in initiation of retinoblastoma tumors; however, additional genetic changes are needed for the continued growth and spread of the tumor. Ex vivo research has shown that in humans, retinoblastoma may initiate from RB1-depleted cone precursors. Notwithstanding, it has not been possible to assess the full spectrum of clonal types within the tumor itself in vivo and the molecular changes occurring at the cells of origin, enabling their malignant conversion. To overcome these challenges, we have performed the first single cell (sc) RNA- and ATAC-Seq analyses of primary tumor tissues, enabling us to dissect the transcriptional and chromatin accessibility heterogeneity of proliferating cone precursors in human Rb tumors. Methods: Two Rb tumors each characterized by two pathogenic RB1 mutations were dissociated to single cells and subjected to scRNA-Seq and scATAC-Seq using the 10× Genomics platform. In addition, nine human embryonic and fetal retina samples were dissociated to single cells and subjected to scRNA- and ATAC-Seq analyses. The scRNA- and ATAC-Seq data were embedded using Uniform Manifold Approximation and Projection and clustered with Seurat graph-based clustering. Integrated scATAC-Seq analysis of Rb tumors and human embryonic/fetal retina samples was performed to identify Rb cone enriched subclusters. Pseudo time analysis of proliferating cones in the Rb samples was performed with Monocle. Ingenuity Pathway Analysis was used to identify the signaling pathway and upstream regulators in the Rb cone-enriched subclusters. Results: Our single cell analyses revealed the predominant presence of cone precursors at different stages of the cell cycle in the Rb tumors and among those identified the G2/M subset as the cell type of origin. scATAC-Seq analysis identified two Rb enriched cone subclusters, each characterized by activation of different upstream regulators and signaling pathways, enabling proliferating cone precursors to escape cell cycle arrest and/or apoptosis. Conclusions: Our study provides evidence of Rb tumor heterogeneity and defines molecular pathways that can be targeted to define new treatment strategies.

Adjuvant use of laser in eyes with macular retinoblastoma treated with primary intravenous chemotherapy.

BACKGROUND: Adjuvant use of laser with systemic chemotherapy for treatment of retinoblastoma may reduce recurrence rates while also causing local side effects. Information is lacking on the effect of laser on visual outcomes. METHODS: A retrospective review of two retinoblastoma centres in the United Kingdom was conducted. Patients were included if there was a macular tumour in at least one eye. Eyes that received chemotherapy alone were compared with eyes that received chemotherapy plus adjuvant laser. RESULTS: A total of 76 patients and 91 eyes were included in the study. Systemic chemotherapy alone was used in 71 eyes while chemotherapy plus laser was used in 20 eyes. Demographic characteristics of both groups were similar. Macular relapse rates were similar between groups: 22/71 (31%) eyes in chemotherapy group and 9/20 (45%) eyes in laser group (p=0.29). There was no increase in vitreous relapses in the laser group (2/20 eyes), compared with the chemotherapy group 10/71 eyes (p=0.99). Survival analysis demonstrated similar time to first relapse between groups. Final visual acuity was equal between groups with 6/15 or better present in 31.1% of eyes in the chemotherapy group and 37.5% of eyes in the laser group (p=0.76). Presence of tumour at the fovea was predictive of final visual acuity, regardless of treatment group. CONCLUSION: Adjuvant laser in the treatment of retinoblastoma is safe and does not lead to increased rate of vitreous recurrence. Final visual acuity is determined by the presence of tumour at the fovea and not the use of laser.

Current Indications of Secondary Enucleation in Retinoblastoma Management: A Position Paper on Behalf of the European Retinoblastoma Group (EURbG).

Secondary enucleation (SE) puts an irreversible end to eye-preserving therapies, whenever their prolongation is expected to violate the presumed state of metastatic grace. At present, it must be acknowledged that clear criteria for SE are missing, leading to empiric and subjective indications commonly related to disease progression or relapse, disease persistence masking the optic nerve head or treatment-related complications obscuring the fundus view. This absence of evidence-based consensus regarding SE is explained by the continuously moving frontiers of the conservative management as a result of diagnostic and therapeutic advances, as well as by the lack of studies sufficiently powered to accurately stratify the risk of metastasis in conservatively treated patients. In this position paper of the European Retinoblastoma Group (EURbG), we give an overview of the progressive shift in the indications for SE over the past decades and propose guidelines to assist decision-making with respect to when SE becomes imperative or recommended, with corresponding absolute and relative SE indications. Further studies and validation of biologic markers correlated with the risk of metastasis are expected to set more precisely the frontiers of conservative management and thus consensual criteria for SE in the future.

Role of ethnicity and socioeconomic status (SES) in the presentation of retinoblastoma: findings from the UK.

BACKGROUND: The relationship between the ethnic background or socioeconomic status (SES) and late retinoblastoma (Rb) presentation in the UK is unclear. We aimed to investigate if such correlations exist in a cohort of non-familial Rb cases. METHODS: A cross-sectional study based at the two centres providing Rb care in the UK. Included were non-familial Rb cases that presented from January 2006 to December 2011. Epidemiological and clinical data were retrieved from medical charts, as well as patients' postcodes used to obtain the Index of Multiple Deprivation (IMD) score. A postal questionnaire was sent to participants' parents to collect further, person-level, information on languages spoken and household socioeconomic position. Statistical correlations to advanced Rb at presentation as well as to treatment by enucleation and need for adjuvant chemotherapy were investigated. RESULTS: The cohort included 189 cases, 98 (51.8%) of which were males. The median age at diagnosis was 16 months (IQR 8-34 months). Of the study patients, 153 (81%) presented with advanced Rb; 78 (41%) with group D and 75 (40%) with group E Rb. A total of 134 (72%) patients were treated with enucleation. South Asian ethnicity and being in the most deprived IMD quintile were associated with a higher likelihood of presentation with advanced disease, but these estimates did not reach statistical significance. Older age at presentation was associated with enucleation and bilateral disease with adjuvant chemotherapy. CONCLUSIONS: In this national UK study of patients with non-familial Rb, there was no evidence of an association of ethnicity or SES and the risk of presenting with advanced disease. These findings may reflect equality in access of healthcare in the UK.